(introduction...)

Introduction
The ecological zones of Sub-Saharan Africa
General crop production constraints and potentials for overcoming them
Technologies with potential for sustainable resource management
Women's underexploited potential
Suggested approaches to sustainable production
Summary
Conclusions
Acknowledgements
References

 

Humphrey C. Ezumah and Nkoli N. Ezumah

Introduction

It is estimated that by the year 2025 the population of Sub-Saharan Africa will double. A major concern is how to feed the population of over 480 million (without South Africa) whose 3 per cent rate of annual population increase is about the highest in the world. Climatic, ecological, and socio-economic problems plague Africa. Poor infrastructure for crop production, handling, and marketing, compounded by climatic extremes, causes fluctuations in food availability and subsequently hunger. About 100 million inhabitants of SubSaharan Africa (or 25 per cent) consume less than 80 per cent of the requirements recommended by the Food and Agriculture Organization of the United Nations (FAO), including the proportion filled by food imports (World Bank 1989). Because the food security of the majority of the Sub-Saharan African population that is dependent upon farming is directly influenced by agriculture, emphasis on agricultural productivity and related activities will most likely alleviate the food deficits of the most vulnerable sector. Production not only must increase but should be sustained in the long term.

The concern for sustainable development is reflected in the growing literature and policy initiatives on the issue. Definitions range from those that base sustainability on ecological balance to those that combine ecological with socio-economic concepts. Dover and Talbot (1987) view a sustainable production system as one whose productivity continues indefinitely with no noticeable degradation of the ecosystem. Earlier, Conway (1985) emphasized sustainability as the ability of a system to maintain its level of productivity in spite of a major disturbance such as is caused by an "intense or large perturbation." These definitions do not give the degree or level of production to be maintained and at what pressure on the environment. Thus the boundaries have not, according to Lynam and Herdt (1988), been ascertained in these definitions. In this paper, the explanation of sustainability that incorporates biophysical, socio-economic, and cultural concepts given by Okigbo (1989) is preferred. He defines a sustainable agricultural production system as "one which maintains an acceptable and increasing level of productivity that satisfies prevailing needs and is continuously adapted to meet the future needs for increasing the carrying capacity of the resource base and other worthwhile human needs" (1989: 3). Thus a production system leads to the development of people if it results in advancement from the current position. Development attains a sustainable level when its processes are controlled and perpetuated by resources within the reach of, and/or controlled by, the system such that any external influences do not upset the equilibrium attained. Highly developed people (or societies) attain a high quality of life using resources that they control or that are accessible to them to "own, maintain or hire" (Okigbo 1989).

The objective of this paper is to examine how agricultural development can be oriented to be highly productive and sustainable. Therefore the main discussion areas in this paper are:

· The ecological zones of Sub-Saharan Africa: their major crops and production constraints.
· General crop production constraints and the potential for over coming them.
· Technologies with potential for sustained resource management.
· Women's underexploited potential.
· Approaches to sustainable crop production in Sub-Saharan Africa.

The ecological zones of Sub-Saharan Africa

Sub-Saharan Africa has over 23 million km2 of land with a potential arable area estimated at 643 million hectares and forest at 700 million hectares, which is being cleared at the rate of 3.7 million hectares per year (World Bank 1989). Only 174 million hectares of the land are currently under cultivation. Sub-Saharan Africa is demarcated into five major ecological zones, which are determined mainly by rainfall and relief (table 11.1).

The humid forests of West and Central Africa

In the humid forests of West and Central Africa, tree crops such as oil-palm (Elaeis guineensis), cocoa (Theobroma cacao), rubber (Hevea braziliensis), and protected economic woody plants are grown in plantations or in multistorey associations with root and tuber crops. Rice is a major crop in both swamps and upland areas in the humid forest zone. Compound land (land immediately adjacent to the compound or homestead, often in permanent cultivation) is particularly important in these areas. Household refuse, including ash and plant and animal wastes, is used to maintain a stable multistorey plant production system. Protected trees, perennial herbaceous plants, including plantains and bananas, together with raffia are mixed with vegetables, spices, yams, and some maize in farms around the homesteads. The trees gradually decrease in number or completely disappear from farms as the distance from homesteads increases.

Soil fertility and structural instability are the most important plant production constraints of this zone. Luxurious forest growth soon gives way to eroded land when clearing is followed by intensive cropping (Kang and Juo 1981; Lal 1989). Soil acidity is common, and weeds, which flourish in the heavy rains, compete with tree and other food crops. Another important effect of forest clearing is loss of plant genetic diversity, exposure of soil to wind and water erosion, and the extinction of useful plant resources (Okigbo 1989). This resource waste is further accentuated by high average human (63 persons/km2 in West Africa and 10/km2 in Central Africa) and animal population pressure, intensive farming, overgrazing, construction development, hunting, and burning. A reduction in maize yield in this zone owing to cloudy skies and reduced insolation has been observed (IITA 1983).

The Southern Guinea Savanna and Derived Savanna

The humid forest of the Southern Guinea Savanna, sometimes called the sub-humid zone of West Africa, has been mostly cleared and cropped for a long period and has been overtaken mainly by grasses and shrubs. At an early stage of succession from forest to savanna is the Derived Savanna, which is better known as Guinea Savanna (Ter Kuile 1987). Rainfall in the Derived Savanna may be slightly higher than that in the Southern Guinea Savanna (table 11.1). Sorghum and maize are important cereals, and root crops (cassava and yams) grow and yield highly.

Table 11.1 Major eco-zones and characteristics in Sub-Saharan Africa

Zone		Number of humid months		Mean annual rainfall		Growing period (days)	Main soils
1. Forest: coastal West some Africa and Central Africa		7-9 +		1400-4000 + (mostly unimodal)		270-365	Mostly acidic (ultisols and oxisols); non-acid (inceptisols, entisols, verti sols, alfisols, etc.)
2a. Derived Savanna		6-7		1300-1500 (bimodal, some areas)		240-270	Moderately leached soils (alfisols, some ultisols, etc.)
2b. Southern Guinea Savanna		5-6		1200-1500 (partially bimodal)		190-240	Mainly alfisols and related soils; acidic ultisols and oxisols in some wetter areas; also entisols and vertisols in some areas
3. Northern Guinea Savanna		4-5		880-1300 (unimodal)		140-200	As above, with greater proportion of non-acid alfisols
4. Sudan Savanna 2 4		500-880		90-140 (unimodal)			Alfisols and some drier aridisols, etc.
5a. Eastern and southern African highlands		7-12		750-1000 (unimodal)		270-365	Ultisols, oxisols, vertisols
5b. Eastern and southern African highlands		5-6		750-1000 (bimodal)		190 240	Alfisols, ultisols. oxisols

Source: Adapted from Papadakis (1966); FAO (1978); Kowal and Kassam (1978); Lawson (1979).

The high infestation of tse-tse fly debars the use of oxen as sources of power; therefore labour at peak growing seasons is a major constraint. This zone is poorly served by roads and marketing systems. Weeds, particularly the parasitic Striga, attack the dominant cereal crops. The soils are relatively rich and are structurally more stable than humid forest soils but are frequently deficient in some major nutrients, whose efficiency may be reduced by negative interaction with minor elements, e.g. phosphorus (P) and zinc (Zn).

The Northern Guinea Savanna

The Northern Guinea Savanna of West Africa, also called the sorghum-millet belt of West Africa, receives lower rainfall than the southern part. It is excellent for maize growth and some of the highest yields in West Africa are obtained from this zone (IITA 1984). Sorghum is also important. However, drought at critical stages of maize development frequently reduces grain yields. High soil temperatures and high evaporation rates are also important constraints (Hullugale 1989). The parasitic weed Striga attacks cereals and grain legumes (cowpea), the two important food-crop groups grown in the Northern Guinea Savanna. The soil is more favourable for cropping and responds to N, P, and S applications. Soil erosion caused by wind and soil crusting and capping has also been reported (Charreau 1970).

The Sudan Savanna

The Sudan Savanna is located to the north of the Northern Guinea Savanna. Rainfall is unimodal, its duration is uncertain, and crop failures are common. Millet and cowpeas are the major food crops in this area. Cereals are grown on about 70 per cent of the total cultivated area of the Sudan Savanna (Matron 1987). Cotton and groundnuts are the major commercial crops and are sometimes grown for export.

The eastern and southern African highlands

The generalizations about the preceding zones are modified by high elevation in Rwanda, eastern Zaire, Burundi, and the mountainous plains of eastern Africa. The monsoon tropical climate and the high incidence of radiation result in extremely high productivity.

In the area of the eastern and southern highlands where rainfall is unimodal, high maize yields are recorded. However, rainfall may limit production. Banana is an important staple and groundnuts are also grown commercially. Coffee and tea, particularly the former, are export crops.

In the area where rainfall is bimodal (March/April to May and November to January), the short duration of the rainfall requires very intensive labour in land preparation and planting, the consequences of which are frequent crop losses. The crops grown are maize, coffee, and bananas. High population pressure on the soils of both highlands, with only 5-7 months of rainfall, causes low productivity. Soil loss is high, particularly in the communal lands of Zimbabwe, where it is reported at 50 tons/ha/yr (Whitlow 1987) and results in reduced yields of crops (Collinson 1987).

There are, therefore, three broad zones: (a) the humid forest zones of West and Central Africa, (b) the savanna zone, demarcated by the level of available rainfall, and (c) the highlands, including plateaux.

General crop production constraints and potentials for overcoming them

Constraints

Paulino (1987) reports that cereals (wheat, maize, sorghum, millet, rice) constitute 54 per cent by calories of the food crops grown in Sub-Saharan Africa, while root and tuber crops (cassava, yams, potatoes, and taros) make up 27 per cent of calories. All other crops (plantains and bananas, grain legumes, fruits and vegetables, etc.) make up the balance of 19 per cent. Many traditional varieties of these crops are low yielding and the improved varieties released do not seem to have made an impact in the Sub-Saharan Africa region. De Bruijn and Fresco (1989) report relatively small increases in cassava yield (23 per cent) compared with maize (55 per cent) in developing countries during 1984-1986 compared with 1961-1965. The yield increases shown in figure 11.1 are small compared with the population increase, which stood at 71 per cent in Africa during the same period. The small increases in production and yield of cassava and maize during the two decades illustrate the small average effect of introducing improved crop varieties into Africa. Increases in other major crops such as yams, rice, wheat, sorghum, and millet were similarly low in comparison with human population increases. Sweet potato, which produces more dry matter per unit area and time than any other crop in Sub-Saharan Africa, is not a preferred crop, but, fed to pigs and poultry, it can be converted to protein and fats.

Fig. 11.1 Area, yield, und production of cassava and maize in Africa, 1961-1965, 1974-1976, and 1984-1986 (Source: adapted from de Bruijin and Fresco 1989)

Insufficient and excess rains, as well as management and socioeconomic factors, also result in reduced productivity. Across the ecological regions of Sub-Saharan Africa constraints are related to the amount and distribution of rains and to poor soil conditions for plant growth. Rainfall in Sub-Saharan Africa is highly variable, ranging from excessive in places such as Debunscha, Cameroon, with 10,000 mm average annual rainfall to about 200-300 mm in some areas of West Africa. Drought-induced crop losses in the drier areas of Sub-Saharan Africa occur frequently (Matron 1987). In the tropical zone, drought-induced crop losses may occur during years in which the rains are poorly distributed (Ter Kuile 1987; Lawson 1985). The incidence of diseases and pests is enhanced by rainfall and soil condition. An example is the noxious weed spear grass (Imperata cylindrica), which thrives in areas where forest vegetation is replaced by grass. Many diseases such as Pythium and Phizoctonium rots occur mainly in high-rainfall areas, as does cassava bacterial blight, Xanthomonas manihoti, which requires high humidity to survive (Lawson and Terry 1984), while the cassava mealybug (Phenacoccus manihoti MF) is very serious during dry seasons (Nwanze et al. 1977; Herren 1989). Multiple soil nutrient deficiencies, especially in areas with a high cropping intensity, low inherent soil fertility characterized by low cation exchange capacity (CEC), high acidity, rapid organic matter decomposition, high P fixation, high erodibility, and leaching -all compounded by a dominance of low activity clay (Kang and Juo 1981) - render most of the soils in Sub-Saharan Africa unsuitable for intensive crop production using available technologies.

Farmers with few resources, a large proportion of whom are women, dominate in Sub-Saharan Africa. They may manage efficiently at their resource level, which, unfortunately, is low in productivity. High resource inputs require more efficient and demanding managerial skills, which should be demonstrated by profit margins in competitive markets and not by ability to survive. Women who dominate in farming have very limited access to production resources.

Institutional and policy constraints have been discussed by Vallaeys et al. (1987), Olayide and Idachaba (1987), and other authors in Mellor et al. (1987). They emphasize the underdeveloped marketing and input/output infrastructure of the agricultural sector, low investment in research, amounting to about 0.5 per cent of gross agricultural product (Vallaeys et al. 1987), poor research-extension-farmer linkages, which reduce the effectiveness of technology transfer (Collinson 1987), and the high dependence of agricultural inputs on imports, which are becoming increasingly costly as foreign exchange becomes scarce. Yet the prices of farm outputs decline.

Potentials for overcoming constraints

In spite of the constraints enumerated above, crop production in SubSaharan Africa could increase tremendously if adequate human and institutional resources were available to manage the biophysical resources. To buttress this statement, Ruttan (1988) noted that the achievement of the level of development attained by developed countries will depend upon Africa's commitment to the investment in the institutional and physical infrastructure required to exploit the production potential of the resources with which Africa is endowed. De Wit et al. (1979) report a calculation by de Hoogh et al. (1976) that shows that, whereas the potential arable land in tropical Africa is 643 million ha, the area in use is only 174 million ha, or 27 per cent.

The same data indicate that yield expressed in 1965 grain equivalent for Africa was only 74,000 million out of a potential 9,474,000 million kilocalories, i.e. only 0.8 per cent. Thus the biophysical resources available in Sub-Saharan Africa and elsewhere in the world are grossly underutilized. Because these calculations were based upon biophysical potentials (fertilizer and water are not limiting, diseases and pests are controlled, optimal available solar radiation is captured), it was concluded that the main obstacles to increased crop production are socio-economic (capital, institutions, policy, culture). Sub-Saharan Africa could resolve its food deficit problem if even 25 per cent of this estimation were attained. How do we manage the resources of crop production (including human, with an emphasis on women farmers) so that resources are sustained? This question calls for a re-examination of the technologies available and their usefulness in sustained resource management.

Technologies with potential for sustainable resource management

Good technologies with missing links

In Sub-Saharan Africa, considerable efforts have been expended on the development of improved cereals, root and tuber crops, and food and fodder legumes by plant breeders, and also on the characterization and identification of the limitations of the soils. Pest control measures have also received attention, particularly from international (IITA, IRRI, ICRISAT, WARDA, ILCA, ICP),1 national, and other research centres and universities in Africa. Agronomists and soil scientists have conducted a lot of research on responses to fertilizer application of various crops in different ecological settings, and breeders and disease and pest control specialists have documented results based on chemical, host plant resistance, biological, and chemical control measures.

Each of these results, introduced into a farmer's system, provides some relief to problems. The ephemeral nature of some of the relief is realized when the breeders' variety yields less than expected in the intensive multistorey crop association system of small-scale farmers (duo and Ezumah 1992), and when the expected response to fertilizer is not realized, either because the increased crop pressure requires higher applications (Wahua 1983; Olasantan 1992), or because the soil physical conditions have deteriorated so much that the effectiveness of fertilizer is reduced in intensive systems (Lal and Greenland 1978). Similarly, the undesirable long-term effects of pest and disease control by a non-integrated approach have been documented (Maxwell 1990). A holistic approach to research and extension, which also incorporates the concepts of integrated pest management (IPM), could reduce the dangers of unsustainable crop production in SubSaharan Africa.

Technical innovation in agriculture is generally not designed so as to exploit the complementary and synergistic effects of the important results for sustained crop production enumerated earlier. Such complementarities are achievable when technologies are developed from current farmers' knowledge base, using multidisciplinary experiences (Norman 1982; Hildebrand 1990). The central thesis is that resourcepoor farmers do not adopt technologies that require costly inputs of labour, cash, and materials or technologies for which inputs are not readily available. These technologies therefore do not fit in the farmers' production environment and frequently break the linkages that enhance resource conservation.

The International Institute of Tropical Agriculture, for example, developed an early maturing erect cowpea that, together with other improved varieties, required frequent applications of insecticide. Among the early varieties were TVX3236 and IT82E-60. As long as chemicals were subsidized when the Nigerian currency, the naira, was relatively strong, some farmers, particularly those on larger farms, grew these cowpea varieties. The majority of the small-scale farmers did not adopt the early, erect types because (a) they required insecticides that were not available or that they could not afford and (b) the vegetation required as animal feed was too scanty. Thus the improved variety that matured early enough in the low-rainfall zones did not satisfy the conditions for its adoption (Carr 1989). With respect to fertilizers, recommendations are available in virtually every country in Sub-Saharan Africa. The limited use of fertilizers, even when prices are subsidized, is attributed to poor distribution systems (Harrison 1987). Although many farmers in south-eastern Nigeria (Unamma et al. 1985) and in Zaire (Osiname et al. 1987) are aware of the importance of fertilizers and herbicides, most are not making use of them because (i) they may not be available either at all or when required, (ii) they are too costly, or (iii) they require equipment that the farmers do not own, e.g. knapsack sprayers. A common feature of the technologies cited - which also include tractorized tillage, liming, short-stalked, high-yielding sorghum for farmers who

may require stalks for fencing or for fuelwood, and zero tillage unaccompanied by a weed control package for reduced tillage systems - is that they do not fit into farmers' production environments because some components that would facilitate their usefulness in existing systems are missing. Adoption of the early cowpea and of dwarf sorghum might, because of high yields, lead to a destruction of vegetation from other environments for animal feed and for fuelwood. It is also noted that the modern practices of conventional agriculture, which comprise land clearing and preparation (tillage systems), fertilization, weed control, and harvesting, have elements of environmental degradation.

Mimicking natural ecosystems

Almost all the sustainable systems currently available in Sub-Saharan Africa mimic natural ecosystems. These systems comprise traditional shifting cultivation, which is sustainable at low population pressures, well-managed multiple-cropping systems (which include compound land systems), the alley cropping system, and the fadama or inland valley systems. These systems may have some or all of the following attributes: extending the duration of growth of the plant community, increasing light-capturing potential through multi-layer interception over a longer period, and recycling nutrients from deep layers. The systems also integrate many groups of plant species - ephemerals, annuals, and perennials - in the same land area. By mimicking nature, microclimates suitable for the growth of many species of plants, and that therefore enhance diversity, are created (Okigbo and Greenland 1976; Juo and Ezumah 1992). Multiple-cropping (i.e. intercropping and rotation) leads to more efficient resource use and this is reflected in yield advantages (Osiru and Willey 1972; Okigbo and Greenland 1976; Willey 1979; Ezumah and Lawson 1984, 1990). Associations that exhibit yield advantage may be long-duration plants intercropped with short-duration plants (Okigbo and Greenland 1976; H. Ezumah 1990) or combinations of short-duration crops belonging to the same family, e.g. sorghum and millet (Willey 1979), or of different species, e.g. sorghum and pigeon pea (Rao and Willey 1983) or maize and cowpea (Ezumah and Ikeorgu 1993). Other advantages of multiple-cropping include improved physical and chemical soil conditions for growth (Lal 1976), reduced soil temperature (Lal 1976; Ikeorgu and Ezumah 1991), reduced soil surface evaporation, and increased water content (Lal 1976). Increased biological activity in the soil (e.g. earthworm activity) in intercropping compared with monocrop rotations (Hullugale and Ezumah 1991) and a reduction in surface runoff and soil loss and therefore a reduction of soil degradation have also been reported for intercropped situations (Aina et al. 1977). In Ouagadougou, Hullugale (1989) showed that undersowing Stylosanthes with maize reduced soil temperature and increased soil moisture, which was significantly improved by conserving moisture through the erection of cross ridges or tying of ridges. Ikeorgu and Ezumah's (1991) results also showed reduced soil temperature in cassava intercropped in four complex mixtures with maize, okra, and egusi melon compared with sole cassava or cassava + maize intercrops. These results highlight the need to focus research on farmers' current systems and to improve on them. They also show the importance of conserving plants and animals in the wild, because their usefulness to humans, apart from the broad concept of ecological balance, is unknown.

Surface mulching

Some of the advantages of multiple cropping are also obtained by surface mulching of the soil with dead material (Lal 1976). Okigbo (1977) studied a wide range of mulching materials including gravel, sawdust from wood, translucent white and black plastics, as well as foliage and twigs from different plant sources including leguminous and non-leguminous plants. The short-term advantages of mulching on an alfisol in Nigeria appear to relate more to improvement of the soil microclimate for plant growth than to chemical properties, because higher crop yields were obtained from the plastic mulches than from the foliages and the twigs. These effects do not, however, negate the long-term benefits of mulching (Lal 1989). A major difficulty of mulching is the procurement of materials. Lawson and Lal (1980) estimated a threshold of 4-6 tons/ha for effective mulching on an alfisol in Nigeria. This quantity of mulch is too much for a lowresource farmer to carry. Akobundu (1980) reported higher maize yield without N fertilization over a five-year period of continuous cropping in association with living legume plants (Psophocarpus palustris and Centrosema pubescens). Little response to N fertilizer was observed in the legume-associated plots compared with the control, which responded to over 60 kg N fertilization per hectare. For greater benefits, a well-established legume plot is required (Mulongoy and Akobundu 1985). Cassava intercropped with maize generates enough mulch to sustain yields. The IITA (1985) reported stable yields of cassava and maize over four years on an alfisol in southern Nigeria. Longer-duration maize (over 120 days to maturity) with high dry matter gave higher yields than shorter-duration maize (less than 100 days to maturity). The short-duration maize allowed in more light to the associated cassava in their intercrop system.

Alley cropping

The most recent innovation in mimicking the natural ecosystem is the alley cropping system (Kang and Wilson 1987). In alley cropping, the multistorey association of the compound land setting is rearranged so that trees occupy adjacent hedges (hedgerows), about 4m apart. Crops are then grown in the alleys between the hedges. Trees are chosen for certain characteristics such as deep rooting (to recycle nutrients), ability to coppice and to produce high biomass (which is pruned for mulching and nutrient release), and, sometimes, rhizobia N-fixing ability. Legume trees in the hedges contribute N in excess of 40 kg/ha to associated crops (Kang 1988). Even non-legumes recycle deeply located nutrients at about 13-19 kg/ha. Although the alley system contributes to moisture conservation, organic residue, and structural and chemical improvements to the soil, a reduction in the yields of associated crops owing to reduced light because of the tree canopy has been observed (Lawson and Kang 1990). Considering its soil improvement features and the stability of alley cropping over a period of years (Kang and Wilson 1987; IITA 1989: fig. 2), alley cropping is a sustainable system that needs refining. Unlike compound farming, it is amenable to large-scale methods. The labour requirements for pruning, which often coincides with other important farm activities (e.g. weeding and harvesting of maize and melon), are a serious setback (Ngambeki 1985). Alley species suitable for acid soils are still being sought. Figure 11.2a shows a rapid decline of maize yields in a continuous cropping system, even if fertilizer is applied. Alley cropping can stabilize maize yields at levels that vary with inputs, e.g. fertilizer (fig. 11.2b). In the latter case, fertilizer augments biologically generated nutrients to sustain maize yields.

Inland valleys

Fig. 11.2 Muize production at IITA, Ibadan. (a) Relationship between length of continuous cultivation and maize yields. (b) Sustainability of maize production in alley cropping systems (Source: Kang and Wilson 1987)

Inland valleys or fadamas, though small individually, total tens of millions of hectares in West and Central Africa. International Institute of Tropical Agriculture estimates for West Africa alone gave about 14 million ha (IITA 1980). Inland valleys are well watered and have enormous potential for producing food, especially rice. In China, inland valleys have been cropped continuously for centuries (duo and Lowe 1986). The neglect of Sub-Saharan Africa's inland valleys, according to the International Institute of Tropical Agriculture (IITA 1990), is attributed to lack of knowledge about their management, which leads to their infection by vectors of many harmful diseases, such as Schistosomiasis, river blindness, malaria, and guinea worms. In addition to water availability, the inland valleys are sustainable and give higher rice yields because they are relatively high in fertility as a result of inflows of nutrients from the uplands. Increased fertility of the inland valleys of Sub-Saharan Africa can be attained by rotating rice with legumes tolerant of water logging, some of which are Crotolaria spp., soybean (Glycine max), and Sesbania spp. Thus, exploitation of the potential for sustainable plant production in the inland valleys of Sub-Saharan Africa requires more research.

Disease and pest control

Some known crop management methods to control diseases and pests include chemical and mechanical measures. These may require high capital and labour inputs. Host plant resistance and biological control measures, though requiring high initial investment at institutional levels, are sustainable and indirectly affordable by the low-resource farmers of Sub-Saharan Africa. Recent examples include the control of cassava bacterial blight (Xanthomonas manihotis) by resistance breeding (Hahn et al. 1979) and the effective reduction of the cassava mealybug pest (Phenacoccus manihoti Mat-Fer) by biological control (Neuenschwander and Hammond 1987). A parasitoid, Epidinocarsis lopezi, introduced from Latin America and released at strategic sites has contributed to the reduction of the cassava mealybug epidemic in Africa.

Many examples of disease and pest resistance through breeding have been documented for various crops in Sub-Saharan Africa. Claims that diseases and pests (except for weeds, for which it has been demonstrated) are controlled by intercropping need further research because reports have been inconsistent (IITA 1978; Francis 1989).

Women's underexploited potential

One of the causes of the "weak agricultural growth" in Africa is the underutilization of human resource potential (World Bank 1989: 2). This is particularly manifested in the gender gap in access to production resources. The majority of African food crop producers who are smallholder farmers, and women in particular, experience great difficulties in increasing production. To achieve sustainable agricultural production it is imperative to eliminate those factors that hinder the productivity of the majority of food producers.

African women are responsible for about 70 per cent of the labour input in food production. Their activities include hoeing, planting, weeding, transportation of crops and planting materials, food processing, and storage. Men, on the other hand, have been largely responsible for bush clearing, land preparation, staking of crops, and hunting (FAO 1982). Recent trends characterizing gender roles in African agriculture have been identified (Guyer 1986: 396-398), namely, that male tasks in agriculture are declining owing to: (a) the decrease in forest cover and game resources; (b) the greater participation of men in out-migration; and (c) male predominance in export crop production. As a corollary, women's agricultural work has been intensified. Factors responsible for this development are that: (a) shorter fallows are now used, resulting in increased weeding; (b) as the distance of farms from homes increases, there is greater demand for the transport of crops and planting materials; (c) as the food trade increases, the demand for food processing increases; and (d) the predominance of men in migration leads to an increased workload for women in food production.

Despite the increased responsibility of African women for food production, their productive capacity is deteriorating because they continue to suffer from less access to production resources and inputs, agricultural innovations, and extension services. Some specific constraints that are important for women farmers in Sub-Saharan Africa concern limited or no access to resources such as land, capital/credit, labour, and agricultural innovations.

Access to land

In most African societies women traditionally had use rights to land (Pale 1976). The introduction of the Western concept of private land ownership has been to the detriment of women (Boserup 1970). Some development programmes in Africa have also exacerbated women's restricted access to land. Pankhurst and Jacobs (1988) report women's loss of land through land reforms in Zimbabwe. The marginalization of women in the allocation of irrigated rice fields to men in the Gambia adversely affected rice production and gender relations and also culminated in the failure of the project (Dey 1981; Carney 1988).

Access to credit

Smallholder farmers, particularly women, who lack access to credit experience great difficulties in purchasing inputs to increase their production. Access to credit is often based on ownership of collaterals such as land or membership of cooperatives and farmers' associations, which many African rural women lack (Loutfi 1980; Cloud 1985). Consequently, most agricultural bank loans in the past went to "absentee" or "progressive" farmers (professionals, top bureaucrats, and military personnel) (Bukh 1979; D'Silva and Raza 1983; Okuneye 1984).

Access to labour

The male predominance in rural-urban migration for wage employment has resulted in the intensification of women's work in agriculture and in labour shortages in food production, particularly in female-headed households (Rogers 1980). Women's lack of access to credit has a concomitant effect on their ability to purchase paid labour (Roberts 1988). A greater number of women consequently dissipate a lot of energy that could be channelled towards increased productivity on their farms in other enterprises such as working as paid labour on other people's farms or providing exchange labour in return for labour received (Guyer 1984; N. Ezumah 1990). Women's cultural obligation to provide labour on their husband's farm also results in limitations on the amount of time they can devote to their own farms (Babalola and Dennis 1988).

Access to improved technologies

The dissemination of information about innovations in agriculture as well as access to training, fertilizers and other inputs, and extension services have been geared mainly to male farmers with adverse effects on women's productivity. Most training in agriculture has been directed to men. The marginalization of women in terms of access to production inputs has often resulted in the deterioration of women's productive capacity (Muntemba 1982). "Progressive" farmers, usually men, have received preferential allocation of extension visits and services (D'Silva and Raza 1983; Okuneye 1984). Some of the adverse consequences of this neglect of women's role in the implementation of agricultural innovations include a loss in adaptive efficiency when women's operational knowledge is not taken into consideration and lower adaptation rates owing to women's lack of access to technology and training (Kumar 1988: 142).

Suggested approaches to sustainable production

Wisdom from farmers' production systems

Systems that have a high potential for sustainability mimic natural ecosystems and ensure continuity in supply of some important resources for plant growth, e.g. vegetation, nutrients, and water, and prevent their losses from soils by erosion. These systems are those practiced by farmers whose habitats scientists are trying to understand. Biological control is one of the benefits of maintaining the ecological diversity of plants and animals.

Therefore, approaches that incorporate farmers' relevant knowledge and experience into designs for improvement will most likely be sustainable, as has been shown in the examples of mimicking natural ecosystems. The Association of Farming Systems Research and Extension (Norman 1982; Okigbo 1989; Hildebrand 1990) emphasizes approaches requiring a thorough diagnosis of existing systems and conditions before designing any improvements and experimenting and testing them in farmers' fields. Improvements will definitely be necessary because the existing farmers' systems, developed in a given set of conditions (such as shifting cultivation at low population densities with bush path highways), break down when practiced in situations for which they are not meant.

Such improvements should gradually build up from existing systems (Hildebrand 1990) instead of replacing them completely. When replacement is the adopted approach, the system breaks down and frustration occurs, as was noted by Nye and Greenland (1960: v), who reviewed the effectiveness of technologies generated in Europe and applied in tropical Africa and observed that "after a quarter of a century of experiment in the African tropics, we have failed to introduce to the forest regions any method of staple food production superior to the system of natural fallowing used in shifting cultivation." The current research emphasis on multiple cropping, agro-forestry, including alley systems, and mulching of various kinds to produce plant cover for the soil represents a refinement of farmers' shifting cultivation to fit emerging situations.

Requirements of new technologies

To be sustainable, new technologies should address the whole farm and interactions in plant production systems (Hildebrand 1990). Donor interest in Farming Systems Research and Extension (FSR/E) may no longer be strong, as was shown by the funding problems of FSR/E and the complete absence of donors during a recent international meeting (AFSR/E annual meeting, East Lansing, Michigan, September 1992). Yet sustainability and FSR/E are compatible concepts because whole farm situations and interactions of their components need to be understood. An implication is that the days of neatly laid out field experiments with one or two factors and high environmental controls may be over (Federer, personal communication, 1991). High levels of variability are to be expected at farm level and more attention to interactions than to the main effects may pay off in understanding farmers' reel situations and problems.

Sub-Saharan Africa and water problems

At optimum water supply and disease and pest control, Linnemann and his co-workers (1979) showed that the potential annual grain production in Sub-Saharan Africa was about 10 billion metric tons. Burningh et al. (1975) estimated that the potential agricultural area in Africa in 1965-1973 was 23 per cent of Africa's total land area. Out of this area, only 6 per cent is cultivated, with a yield of 1,000 kg/ha, i.e. about 10 per cent of the 10,000 kg/ha potential. Burningh et al. (1975) concluded that the problem is one more of social and economic than of biophysical potential. Nevertheless, biophysical factors are of great importance if this potential is not exploited in a sustainable manner. Many of the improved crop varieties currently in use in Sub-Saharan Africa do not yield as much as they would if adequate water were available. In the humid zones of West and Central Africa, water distribution is such that crops are oversupplied for certain months of the year and undersupplied in others. A lack of water is also noted in some areas in the humid zone because of poor distribution, which often reduces the duration of crop growth (de Wit et al. 1979). Eastin et al. (1969) have shown that moisture stress adversely affects inflorescence development and grain filling and leads to inefficient use of nutrients. With stress, either fertilization is inhibited or grains that are already fertilized abort. Irrespective of breeders' expected yields, crop yields decline because of the reduced duration of growth attributed to the moisture stress of cereal grains (de Wit et al. 1979) or of roots and tubers (Lawson 1985). An urgent technical input is to ensure timely water distribution for plant growth. Even for cassava, which is tolerant of moisture stress, storage root yield is decreased during the dry season months of the transitional zone of West Africa (Lawson 1985).

Implications for plant breeding

For most plant breeders, favourable yields are based on high economic yields and the high harvest indices of improved varieties per unit of space and time. Varieties are usually evaluated in monocropping systems using the recommended levels of fertilizer and pest control. Evidence now available suggests that these values need to be reassessed in plant production systems aimed at sustainable development. To conserve soil resources, there is a need to conserve biological life: living organisms can be adversely affected by pesticides and other chemicals; ploughing accelerates soil and nutrient losses owing to erosion and leaching; good harvests at the expense of leaves, stems, and other plant parts may be detrimental because the additional vegetative materials needed for mulching the soil are lost. In highly vegetative plants, nutrients that could have been leached off or volatilized from soil may be held in plant parts and later released during decomposition.

Fig. 11.3 Effects on cassava root yields of insecticide protection applied to intercropped cowpeas in an IITA experiment in southern Nigeria, 1987/88 (Source: unpublished data from IITA Experimental Service)

The age of sustainability calls for a modification of breeding objectives. It may require new approaches in testing improved varieties and a re-examination of selection procedures. A trait lost may be hard to recover at later stages in a breeding cycle. An example is cassava, whose shoot and root yields may be reduced significantly by spraying cowpea intercropped with the cassava as compared with unsprayed cowpea and cassava (fig. 11.3). Without a systems approach, this interaction may be missed because cowpea protected from insect attack by spraying yielded higher than when unsprayed. Thus the limited objective of increasing cowpea yield is achieved but the broader objectives of ecological balance and of increasing total yield are not attained.

The lack of involvement of users in the development of technologies can lead to non-acceptance of the results. The success of intensive agricultural development in Taiwan is mainly the result of farmer pressure on researchers. In a study of 150 selected projects by US firms, Merrill-Sands (1992) reported a failure rate of about 67 per cent and a success rate of 15 per cent in cases where user influence on the products developed was characterized by hostility and distrust. The exact opposite, 67 per cent success and 14 per cent failure, was observed when client pressure or demand-pull led to product development. The high rate of cassava (TMS 30572) and sweet potato (TIB1) adoption in West Africa, particularly in Nigeria and Cameroon, respectively, appears to relate more to their development in unfertilized soil, which may have simulated the farmers' soil conditions, than to any other factor.

Virtually all the crops that generate export income, such as cocoa, coffee, and oil-palm, are declining in importance in the world market. For increased export earnings, Sub-Saharan Africa may need to produce specialized products in which it commands some advantages. The luxuriant vegetation, fruits, and nuts in African landscapes contain important oils, some protein, lubricants, and condiments (Okigbo 1980). Their potential benefits to Sub-Saharan Africa and in the world market remain unknown. For example, the cash income derived from some protected isolated stands of trees (Elaeis guineensis, Irvingia gabonensis, Raphia spp., and Bytyrospermum paraatoxum) in southern Nigeria in 1980 was at least 2.3 naira per tree per day or over 10 naira (US$0.5) at 1980 rates (Okafor 1980). Multiplication and improvement of important plants can be effected by biotechnology, which also has considerable potential in health care (medicine, nutrition) and in the chemical and cosmetic industries. New, improved crops with desirable characteristics, as well as cheap pest and disease control measures, are other potential benefits of biotechnology that Sub-Saharan Africa may miss out on if action is not taken to utilize existing facilities and create new ones if necessary.

Enhancing women's productivity

To attain sustainable development arising from the increased agricultural productivity of Sub-Saharan Africa, the human resource potentials of both men and women should be developed. Concrete efforts should be geared towards enhancing the productivity of all those involved in food crop production. As women are now responsible for the bulk of the food crops produced on small farm holdings, the emphasis should be on providing them with access to the resources and inputs necessary to increase their productive capacity (specific resources have already been discussed).

Summary

This paper has discussed the potential for developing sustainable plant production systems for Sub-Saharan Africa. Only a small fraction of the biophysical potential for crop production in Sub-Saharan Africa is exploited. Although the constraints on plant production are many, they can be reduced to three main focus areas: rainfall, soil related issues, and human resource management.

There is a need to develop methods of conserving the available water and to invest in water storage, particularly for those semi-arid areas of Sub-Saharan Africa where there is a serious lack of moisture. This requires investment, but approaches currently used by farmers (stone and plant barriers, surface catchments, tied ridges) need to be improved and inland valleys should be exploited. All these require more research. Agro-forestry species tolerant of acid soils and adapted to the semi-arid zone should be identified and evaluated for their usefulness in alley or related systems.

In the humid forests, the Guinea and moist savannas, and the highlands of eastern Africa, agro-forestry systems, multiple-cropping systems, and surface mulching using appropriate live mulch species need to be studied further. These have elements of sustainability that require additional research prior to their wide application. Of particular importance is the interaction of live mulches with soil moisture, especially in dry areas. With the increasing cost of imported chemicals, fertilizer research should be redirected to determining the minimum levels required for sustained yields and to augment nutrients generated through biological activity.

Holistic approaches to technological developments pay off in terms of their ease of adoption. Step-wise approaches to technology development, using farmers' current systems as the base, appear to have merits for the small-scale farmers of Sub-Saharan Africa. Research into whole farm systems requires a revision of the operational approach. Farm-level research is very complex and involves many interactions; it therefore requires multidisciplinary team efforts. Less rigorous but useful analytic approaches should be devised for interpreting data. Most of the farmers in Sub-Saharan Africa are women. Their neglect in resource allocation should be redressed by gearing efforts towards enhancing their productivity.

Finally, biotechnology may be the cheapest hope if it is applied to resolving some of the constraints, for example through multiplication of improved varieties, particularly clonal materials (Zok and Nyochembeng 1992), conservation of wild and exotic species, and breeding for disease and pest resistance and much other gene-related research. Regional laboratories to handle this specialized work need to be created, staffed, and funded for the mutual benefit of the countries of Sub-Saharan Africa, and special management procedures devised for the laboratories. Some existing laboratories - for example, the Jay P. Johnson Biotechnology Laboratory, Ekona, Cameroon, and the International Institute of Tropical Agriculture Biotechnology Laboratory at Ibadan, Nigeria - could be expanded to serve parts of the region, and the possibility of establishing others needs to be evaluated. Courses in biotechnology to acquaint researchers and policy makers with its potential (similar to the one designed by Ferguson et al. 1992) could be modified to fit Sub-Saharan African conditions and videotaped for popular use. Such a course could remind researchers and policy makers of the usefulness of cell biology in agriculture and of the basic training requirements.

Conclusions

1. Sub-Saharan Africa has more than enough biophysical resources to produce more food and other plants at sustained levels.

2. Research should be directed to exploiting existing biological complementarities in a holistic manner. Inorganic inputs should be used to complement, not to replace, biological inputs.

3. Post-harvest losses constitute a major source of productivity loss in Sub-Saharan Africa.

4. Since most crops in Sub-Saharan Africa are produced by women, gender issues are very important and should be addressed in developing plant production and utilization technologies.

5. Small-scale farming is not necessarily bad, and increased production does not necessarily call for increased farm size.

6. Given the adverse effects of mechanization in terms of the degradation of soil resources in the tropics, one must be cautious about introducing mechanization, especially because it is not a panacea for increased production and yield (see 5).

7. With serious effort and resource commitment, the perennial problem as regards water for crop production and for human needs could be resolved. This is an area in which investment probably could be made to pay, bearing in mind that some parts of California, Nevada, and Israel, for example, which produce surplus food, are in deserts.

8. Continued conservation of species diversity, especially some wild species, is advocated. What is wild today may find a use tomorrow.

9. The potential of biotechnology needs to be exploited through organized groupings of Sub-Saharan African regions to invest in gene-related research.

Acknowledgements

We are grateful to Mr. George Gamze for help in reproducing this paper. To Mrs. C. N. F. Poubom, Mr. A. E. Efite, and Dr. Charles Yamoah we give thanks for proofreading the manuscript and making useful suggestions. In spite of these contributions, all responsibility for the contents of this paper is that of the authors.

References

Aina, P. O., R. Lal, and G. S. Taylor. 1977. Soil crop management in relation to soil erosion in the rainforest of Western Nigeria. In: Soil Erosion Prediction and Control. Soil Conservation Society of America, Special Publication 21: 75-84.

Akobundu, 1. O. 1980. Live mulch: A new approach to weed control and crop production in the tropics. In: British Crop Protection Conference: Proceedings of the 1980 British Weed Control Conference, 17-20 November, Brighton, England. Oxford: ARC Weed Research Organization, pp. 377-382.

Babalola, S. O. and C. Dennis 1988. Returns to women's labour in cash crop production: Tobacco in the Igboho, Oyo State, Nigeria. In: J. Davidson (ed.), Agriculture, Women and Land: The African ExpeHence. Boulder and London: Westview Press, pp. 79 89.

Boserup, E. 1970. Woman's Role in Economic Development. New York: St. Martin's Press.

Bruijn, G. H. de and L. O. Fresco. 1989. The importance of cassava in world food production. Netherlands Journal of Agricultural Science 37: 21 34.

Bukh, J. 1979. The Village Woman in Ghana. Uppsala, Sweden: Scandinavian Institute of African Studies.

Burningh, P., H. D. J. Van Heemst, and G. J. Staring. 1975. Computation of the absolute maximum food production of the world. Department of Tropical Soil Science, Agricultural University, Wageningen, The Netherlands.

Carney, J. A. 1988. Struggles over land and crops in an irrigated rice scheme: The Gambia. In: J. Davison (ed.), Agriculture, Women and Land: The African Experience. Boulder and London: Westview Press, pp. 59-78.

Carr, J. S. 1989. Technology for Small-scale Farmers in Sub-Saharan Africa. Experience with Food Crop Production in Five Major Ecological Zones. Technieal paper no. 109. Washington D.C.: World Bank.

Charreau, C. 1970. Traditional Afriean agricultural systems and their improvement. FAO/IITA Conference on Shifting Cultivation, Ibadan, Nigeria, mimeo.

Cloud, K. 1985. Women's productivity in agricultural systems: Considerations for project design. In: C. Overholt, M. B. Anderson, K. Cloud, and J. E. Austin (eds.), Gender Roles in Development Projects. A case book. West Hartford, Conn.: Kumarian Press, pp. 17 56.

Collinson, M. 1987. Potential and practice in food production technology development: Eastern and southern Afriea. In: J. W. Mellor, C. L. Delgado, and M. J. Blackie (eds.), Accelerating Food Production in Sub-Saharan Africa. Baltimore, Md.: Johns Hopkins University Press.

Conway, G. R. 1985. Agroeeosystem analysis. Agricultural Administration 20: 1 25.

Dey, J. 1981. Gambian women: Unequal partners in riee development project? In: N. Nelson (ed.), African Women in the Development Process. London: Frank Cass, pp. 109-122.

Dover, M. and L. M. Talbot. 1987. To Feed the Earth: Agro-ecology for Sustainable Development. Washington D.C.: World Resources Institute.

D'Silva, C. and M. R. Raza. 1983. Equity considerations in planning and implementing rural development projects in Nigeria: An evaluation of the Funtua Project. In: B. L. Green Shield and M. A. Bellamy (eds.), Rural Development Growth and Inequity. IAAE Occasional Paper no. 3. Brookfield, Vt.: Ashgate Publishing, pp. 101-106.

Eastin. J. O., F. A. Haskins, C. Y. Sullivan, and C. H. M. Van Bavel. 1969. Physiological significance of internal water relations to crop yield. In: Physiological Aspects of Crop Yield. Madison, Wis.: Ameriean Soeiety of Agronomy and Crop Seience Society of America, pp. 53-85.

Ezumah, H. C. 1990. Maize genotypes for intercropping with cassava in Southern Nigeria. Yield responses. Discovery and Innovation (African Academy of Sciences) 2(2): 63 72.

Ezumah, H. C. and 1. E. G. Ikeorgu. 1993. Population and planting pattern effects on intercropped maize and cowpea. Journal of Agronomy and Crop Science 170: 187-194.

Ezumah, H. C. and T. L. Lawson. 1984. Maize plant "architecture". Important factor in intercropping with cassava. IITA Research Highlights. Ibadan, Nigeria: IITA, pp. 96-99.

---- 1990. Cassava and maize intercropping systems. 1. The effects of varieties and plant population. Journal of Agronomy and Crop Science 164: 334 342.

Ezumah, N. N. t990. Women in development: The role of lgbo rural women in agricultural production. Unpublished Ph.D. dissertation, University of Ibadan, lbadan, Nigeria.

FAO (Food and Agriculture Organization of the United Nations). 1978. Food Balance Sheets and Per Caprta Food Supplies. Rome: FAO.

---- 1982. Follow-up to WCARRD: The Role of Women in Agricultural Production. Rome: FAO.

Ferguson, N. H., P. E. Adams, and R. E. Franklin. 1992. A plant biotechnology course in distance delivery. Journal of Natural Resources and Life Sciences Education 21(2): 133-136.

Francis, C. A. 1989. Biological efficiencies in multiple cropping systems. In: Advances in Agronomy, vol. 42. New York: Academic Press.

Guyer, J. I. 1984. Naturalism in models of African production. Man 19: 371-388.

---- 1986. Women's role in development. In: R. J. Berg and J. S. Whitaker (eds.), Strategies for African Development. Berkeley: University of California Press, pp. 393 421.

Hahn, S. K., E. R. Terry, K. Leuschnor, I. O. Akobundu, C. Okali, and R. Lal. 1979. Cassava improvement in Africa. Field Crop Research 2: 193-226.

Harrison, P. 1987. The Greening of Africa. Harmondsworth, Middlesex: Penguin Books.

Herren, H. R. 1989. IITA/Africa-wide biological control programme: History, achievements and prospects for sustainable pest control in Africa. In: Seminar Report: integrated Pest Management, 5 6 Sept 1988. Sem, Asker, Norway: NORAGRIC, pp. 15-32.

Hildebrand, P. E. 1990. Agronomy's role in sustainable agriculture: Integrated farming systems. Journal of Production Agriculture 3(3): 285 288.

Hoogh, J. de, M. A. Keyser, H. Linneman, and H. D. J. van Heemst. 1976. Food for a growing world population: Some of the main findings of a study on the long-term prospects of the world food situation. European Review of Agricultural Economics 3: 459-499.

Hullugale, N. R. 1989. Effect of tied ridges and undersown Stylosanthes hamata (L) on soil properties and growth of maize in Sudan Savanna of Burkina Faso. Agriculture, Ecosystems and Environment 25(1): 39-51.

Hullugale, N. R. and H. C. Ezumah. 1991. Effects of cassava-based cropping systems on physico-chemical properties of soil and earthworm casts in a tropical Alfisol. Agriculture, Ecosystems and Environment 35: 55-63.

IITA. 1978, 1980, 1983, 1984, 1985, 1989, 1990. Annual Report. Ibadan, Nigeria: International Institute of Tropical Agriculture.

Ikeorgu, J. E. G. and H. C. Ezumah. 1991. Some analytical aspects of cassava/maize/ eguei/okra melon complex mixture: Soil temperature in relation to leaf area variation. Field Crops Research 27: 51-60.

Iuo, A. S. R. and H. C. Ezumah. 1992. Mixed root crop ecosystems in the wetter regions of Sub-Saharan Africa. In: C. J. Pearson (ed.), Field Crop Ecosystems of the World. Amsterdam: Elsevier Scientific Publishers, pp. 243-258.

Juo, A. S. R. and 1. A. Lowe (eds.) 1986. Wetland and Rice in Tropical Sub-Saharan Africa. Ibadan, Nigeria: IITA.

Kang, B. T. 1988. Nitrogen cycling in multiple cropping systems. In: J. R. Wilson (ed.), Advances in Nitrogen Cycling in Agricultural Ecosystems. Wallingford, UK: CAB International.

Kang, B. T. and A. S. R. Juo. 1981. Management of soil with low activity clays for food crop production in tropical Africa. In: Proc. International Soil Classification Workshop, Kigali, Rwanda. Technical Monograph, Soil Management Support Service, USDA, Washington D.C.

Kang, B. T. and G. F. Wilson. 1987. The development of alley cropping as a promising agroforestry technology. In: H. A. Stepler and P. K. R. Nair (eds.), Agroforestry: A Decade of Development. Nairobi: ICRAF, pp. 227--243.

Kowal, J. M. and A. H. Kassam. 1978. Agricultural Ecology of Savanna: A Study of West Africa. Oxford: Clarendon Press.

Kumar, S. K. 1988. Women's role and agricultural technology. In: J. W. Mellor, C. L. Delgado, and M. J. Blackie (eds.), Accelerating Food Production in Sub-Saharan Africa. Baltimore, Md.: Johns Hopkins University Press, pp. 135 147.

Lal, R. 1976. Soil Erosion Problems and an Alfisol in Western Nigeria and Their Control. IITA Monograph no. 1, Ibadan, Nigeria.

---- 1989. Conservation tillage for sustainable agriculture: Tropics vs temperate environments. In: Advances in Agronomy, vol. 42. New York: Academic Press, pp. 85 119.

Lal, R. and D. J. Greenland. 1978. Effect of conditioners and moisture content on temperature profile and infiltration rate of a vertisol. In: W. W. Emerson, R. D. Bound, and A. R. Dexter (eds.), Modification of Soil Structure. London: John Wiley, pp. 191-198.

Lawson, T. L. 1979. Agroclimatology section. IITA Annual Report.

---- 1985. Agro-climatic consideration for cassava cropping. IITA Research Highlights, 1981-1984. Ibadan, Nigeria: Farming Systems Program, IITA.

Lawson, T. L. and B. T. Kang. 1990. Yield of maize and cowpea in alley cropping systems in relation to available light. Agricultural and Forest Meteorology 528: 347 357.

Lawson, T. L. and R. Lal. 1980. Response of maize to surface and buried straw mulch on a tropical Alfisol. In: R. Lal (ed.), Soil Tillage and Crop Production. Ibadan, Nigeria: IITA, pp. 63 74.

Lawson, T. L. and E. R. Terry. 1984. Weather and plant disease in Africa. In: D. L. Hawksworth (ed.), Advancing Agricultural Production in Africa. Proceedings of CAB's First Scientific Conference, Arusha, Tanzania, 12 18 February 1984. Slough, UK: CABI, pp. 314 320.

Linnemann, H., J. de Hoogh, M. A. Keyser, and H. D. J. van Heemst. 1979. MOIRA: Model of International Relations in Agriculture. New York: North-Holland.

Loutfi, M. F. 1980. Rural Women Unequal Partners in Development. A Wep study. Geneva: ILO.

Lynam, J. K. and R. W. Herdt. 1988. Sense and sustainability: Sustainability as an objective in international agricultural research. Paper presented at a CIP Rockefeller Conference on Farmers and Food Systems, Lima, Peru, September.

Matlon, P. J. 1987. The West African Semi-arid Tropics. In: J. W. Mellor, C. L. Delgado, and M. J. Blackie (eds.), Accelerating Food Production in Sub-Saharan Africa. Baltimore, Md.: Johns Hopkins University Press.

Maxwell, G. F. 1990. Integrated pest management: Considerations for success in developing countries. In: S. K. Hahn and F. E. Caveness (eds.), Integrated Pest Management for Tropical Root and Tuber Crops. Proc. Workshop on the Global Starus of; and Prospects for, IPM for Root and Tuber Crops in the Tropics. Ibadan, Nigeria: IITA.

Mellor, J. W., C. L. Delgado, and M. J. Blackie (eds.) 1987. Accelerating Food Production in Sub-Saharan Africa. Baltimore, Md.: Johns Hopkins University Press.

Merrill-Sands, D. 1992. Strategic initiatives in roles for FSR/E: Institutional linkages - linkages and impact: Station Research. 12th Annual AFSRE (Association of Farming Systems Research and Extension) meeting, 13-18 September, Michigan State University, East Lansing.

Mulongoy, K. and I. O. Akobundu. 1985. Nitrogen uptake in live mulch systems. In: B. T. Kang and J. van der Heide (eds.), Nitrogen Management in Farming Systems in Humid and Sub-humid Tropics. Harren: Institute of Soil Fertility, pp. 285 290.

Muntemba, S. 1982. Women as food producers and suppliers in the twentieth century: The case of Zambia. Development Dialogue 1-2: 29-50.

Neuenschwander, P. and W. N. O. Hammond. 1987. Biological control of the cassava mealybug, Phenacoccus manihoti, in Africa: A review of field studies. In: S. K. Hahn and F. E. Caveness (eds.), Integrated Pest Management for Tropical Root and Tuber Crops. Ibadan, Nigeria: IITA, pp. 42-57.

Ngambeki, D. S. 1985. Economic evaluation of alley cropping Leucacna with maizemaize and maize-cowpea in southern Nigeria. Agricultural Systems 17(4): 243258.

Norman, D. W. 1982. The Farming Systems Approach to Researck. Farming Systems Research Paper no. 3, Kansas State University, Manhattan, Kansas.

Nwanze, K. F., K. Leuchner, and H. C. Ezumah. 1979. The cassava mealybug: Phenacoccus sp. in the Republic of Zaire. PANS 25(2): 125 130.

Nye, P. H. and D. J. Greenland. 1960. The Soil under Shifting Cultivation. Technical Communication no. 51, Commonwealth Agricultural Bureau, England.

Okafor, J. C. 1980. Edible indigenous woody plants in rural economy of Nigeria forest zone. Forest Ecology and Management 3: 45 55.

Okigbo, B. N. 1977. Effects of mulching with a range of materials on crop yield. In: Mulching and soil management. IITA, Annual Report, Farming Systems Program.

---- 1980. Ahajioku Lecture. Government Printer, Ministry of Information and Culture, Imo State, Nigeria.

---- 1989. Development of Sustainable Agricultural Production Systems in Africa: Roles of the International Agricultural Research Centers and National Research Systems. First Distinguished African Scientist Lecturer Seties, IITA, Ibadan, Nigeria.

Okigbo, B. N. and D. J. Greenland. 1976. Intercropping systems in tropical Africa. In: R. 1. Papendick, P. A. Sanchez, and G. B. Triplett (eds.), Multiple Cropping. Special Publication 27. Madison, Wis.: American Society of Agronomy, pp. 63-101.

Okuneye, B. 1984. Farmers' characteristics and the theory and strategy of agricultural under-development and development. Paper presented at the National Seminar on Innovative Approaches to Development Theory. 23-27 January, Nigerian Institute for Social and Economic Research (NISER), University of Ibadan, Ibadan, Nigeria.

Olasantan, F. O. 1992. Nutrient requirement of cassava (Manihot esculenta Grantz)/ maize (Zea Mays L) intercrop. Ph.D. thesis, University of Ibadan, Nigeria.

Olayide, S. O. and F. S. Idachaba. 1987. Input and output marketing systems: A Nigerian case. In: J. W. Mellor, C. L. Delgado, and M. J. Blackie (eds.), Accelerating Food Production in Sub-Saharan Africa. Baltimore, Md.: Johns Hopkins University Press.

Osiname, O. A., C. Bartlett, N. Mbulu, L. Simba, and K. Land. 1987. Diagnostic survey of cassava-based cropping systems in two ecological zones of gas-Zaire. In: H. C. Ezumah and D. S. O. Osiru (eds.), Cassava Based Cropping Systems Research. Ibadan, Nigeria: IITA.

Osiru, D. S. O. and R. W. Willey. 1972. Studies on mixtures of dwarf sorghum and beans (Phaseous vulgaris) with particular emphasis on plant population. Journal of Agricultural Research, Cambridge 79(3): 531-540.

Pala, A. O. 1976. African Women in Rural Development: Research Priorities. OLC (Overseas Liaison Committee, American Council on Education) Working Paper no. 12, Washington D.C., December.

Pankhurst, D. and S. Jacobs. 1988. Land tenure, gender relations and agricultural production: The case of Zimbabwe's peasantry. In: J. Davison (ed.), Agriculture, Women and Land: The African Experience. Boulder and London: Westview Press.

Papadakis, J. 1966. Crop Ecologic Survey in West Africa, vols. I and II. Rome: FAO.

Paulino, L. A. 1987. The evolving food situation. In: J. W. Mellor, C. L. Delgado, and M. J. Blackie (eds.), Accelerating Food Production in Sub-Saharan Africa. Baltimore, Md.: Johns Hopkins University Press, chap. 23.

Rao, M. R. and R. W. Willey. 1983. Effect of genotype in cereal/cowpea intercropping on the alfisols of semiarid tropics of India. Experimental Agriculture 19: 67 78.

Roberts, P. A. 1988. Rural women's access to labour in West Africa. In: S. B. Stichter and J. L. Parpart (eds.), Patriarchy and Class: African Women in the Home and the Workforce. Boulder, Colo.: Westview Press, pp. 97-144.

Rogers, B. 1980. The Domestication of Women: Discrimination in Developing Societies. London: Kegan Paul.

Ruttan, V. W. 1988. Sustainability is not enough. American Journal of Alternative Agriculture 3: 128 130.

Ter Kuile, C. H. H. 1987. The humid and sub-humid tropics. In: J. W. Mellor, C. L. Delgado, and M. J. Blackie (eds.), Accelerating Food Production in Sub-Saharan Africa. Baltimore, Md.: Johns Hopkins University Press.

Unamma, R. P. A., S. O. Odurukwe, H. E. Okereke, L. S. O. Ene, and O. O. Okoli. 1985. Farming Systems in Nigeria. Agricultural Extension & Research Liaison Services, National Root Crops Research Institute, Umudike, Umuahia, Nigeria.

Vallaeys, G., M. T. Silvestre, M. J. Blackie, and C. L. Delgado. 1987. Development and extension of agricultural production technology. In: J. W. Mellor, C. L. Delgado, and M. J. Blackie (eds.), Accelerating Food Production in Sub-Saharan Africa. Baltimore, Md.: Johns Hopkins University Press.

Wahua, T. A. T. 1983. Nutrient uptake by intercropped maize and cowpeas and a concept of nutrient supplementation index (NSI). Experimental Agriculture 19: 263 275.

Whitlow, R. 1987. A national soil survey for Zimbabwe. Journal of Soil and Water Conservation, July/August.

Willey, R. W. 1979. Intercropping - Its importance and research needs. Part I. Competition and yield advantages. Field Crops Abstracts 32(1): 1 10.

Wit, C. T. de, H. H. Van Laar, and H. van Keulen. 1979. Physiological potential of

crop production. In: J. Sneep and A. J. T. Hendriksen (eds.), Plant Breeding Perspectives. Wageningen, The Netherlands: PUDOC, pp. 47-82.

World Bank. 1989. Sub-Saharan Africa. From Crisis to Sustainable Growth. A Long Term Perspective Study. Washington D.C.: World Bank.

Zok, S. and L. M. Nyochembeng. 1992. Micropropagation of a tropical tuber food crop, Xanthosoma Sagittifolium (L) Schott, in Cameroon. Jay P. Johnson Biotechnology Laboratory, Institute of Agronomic Research, PMB 25 Buea, Cameroon, mimeo.

(introduction...)

Introduction
Livestock production, productivity, and feed resources
The effect of government policy on livestock production
Suggested solutions
Summary and conclusions
References

 

Saka Nuru

Introduction

The livestock industry is an economic enterprise and can also be considered as a "survival enterprise" for millions of herdspeople throughout tropical Africa, especially in the arid, semi-arid, and subhumid areas. Among the multiple roles of the livestock industry, food production and gainful employment are the most important. Over 12 million people in West Africa, of whom over 3 million are in Nigeria, depend primarily on livestock for their survival, while over 70 million people in the same region depend on livestock and livestock-related enterprises for their livelihood (Nuru 1982, 1983; McDowell and DeHaan 1986). One-third of the African continent's livestock population is in West Africa.

How can the African continent, particularly the Sub-Saharan region, increase its livestock product production to meet the everincreasing demands of its people now and in the future, using all available natural resources, with no or minimum environmental degradation? Above all, how may the environment be preserved or sustained for future economic development when major environmental constraints such as drought and erosion could retard future progress in development?

Land degradation (soil erosion), drought, desert encroachment, etc. pose a significant threat to the use of land for crops and livestock production, especially in the arid and semi-arid zones where agricultural activities are the main occupation of the people of Sub-Saharan Africa. To prevent further deterioration and to increase the productivity of food animals, it is necessary to act now.

Because of its economic and social significance, the livestock enterprise must be considered or viewed holistically: the animal, its environment, and productivity. It is the interaction between the physical environment and the animal's genetic make-up that determines productivity and even the survival of both animal and plant species within a given ecosystem. In this holistic approach, human factors such as culture and social and economic status as related to other production factors are also important because they influence productivity. Most African cattle are still in the hands of pastoral livestock owners - the Fulanis, Shuwas, and Fulas in West Africa and the Masais in East Africa. Their husbandry methods are indigenous and based on lowinput systems. However, their survival strategy is influenced by seasonal migration to areas with optimum forage resources to feed their animals. This has an effect not only on animal productivity but also on the ecosystem.

Livestock production, productivity, and feed resources

When considering ecological stability and increased animal protein production from domestic animal species, the two main natural factors of production are:

· the animals - in this case the ruminants but, to a lesser extent, the monogastrics;
· the land and climatic conditions.

Other factors of production are credit facilities, marketing, and the socio-economic status of the herd owners. These factors do not have a direct effect on environmental degradation, whereas the cultural practices in the husbandry system do.

The animal species: Contribution and spatial distribution

Among domestic animals, the ruminants - for example, cattle, sheep, and goats - form the largest number and are of paramount social and economic importance in tropical Africa. There are several reasons why ruminants should be given special attention when considering ecological change in Sub-Saharan Africa.

First, they supply the bulk of livestock products. The ever-increasing demand for these products owing to increased human population and better health education justifies greater attention to animal production if the continent is to avoid a huge animal protein deficit.

Secondly, because of the large population of ruminants and their dependence mainly on global grazing, large areas, especially in West and East Africa, are in danger of irreversible soil degradation and desertification. Ruminants, though not the sole factor in these ecological disasters, contribute through overgrazing and subsequent soil compaction and wind erosion. Their survival is based on genotype adaptability to the fragile environment and the vagaries of climatic conditions.

Cattle and a few other large ruminants constitute 83 per cent of food animals and produce over 45 per cent of meat products and over 90 per cent of available domestic milk supply. Sheep and goats (medium-large stock), on the other hand, constitute 15 per cent of the total number of food animals and contribute about 35 per cent of meat, as well as fibre. As of 1990, 187.8 million cattle, 205.0 million sheep, 173.9 million goats, and 13.6 million pigs were estimated to be in Africa (FAO 1991: 191 and 194). Of these, approximately 178.6 million cattle, 162.4 million sheep, 157.8 million goats, and 13.5 million pigs were in Sub-Saharan Africa. Sub-Saharan livestock produced 6.7 million metric tons of meat (slaughter weight), 14 million metric tons of milk, and 0.9 million metric tons of hens' eggs (FAO 1991: 199-226).

However, there is a higher elasticity of demand than of supply. In West Africa alone, a deficit of 2-4 million tons of meat and 6.5-9.0 million tons of dairy products is envisaged by the year 2000 (McDowell and DeHaan 1986). Table 12.1 shows the distribution of some animal species in Africa compared with world estimates These animals are not evenly distributed across the African continent. As shown in table 12.2, for the West African region, the semiarid zones contain the largest number of ruminant species (16. TLU1) compared with the arid (10.8 TLU), sub-humid (6.2 TLU), and humid zones (4.3 TLU) (Jahnke 1982; McDowell and DeHaan 1986). In terms of stocking density (table 12.3), the arid zone has a low livestock per unit area (2.7 TLU/km2) compared with the semiarid zone (11.1 TLU/km2). Thus the semi-arid areas have more animals per km2 but this is possible because of higher land productivity The highest number of ruminants is found in this zone in West Africa Although the sub-humid and humid zones have greater forage potential, the climate and prevalence of typanosomes limit the use of these two zones for raising ruminant livestock, hence the very low numbers per unit area (2.2 TLU/km2) in the humid zone.

Table 12.1 Livestock numbers in Sub-Saharan Africa, West Africa, and the world, 1990

	Cattle	Sheep	Goats	Pigs
World (m. head)	1,279.3	1,190.5	557.0	856.7
Sub-Saharan Africa (m. head)	178.6	162.4	157.8	13.5
% of world	14.0	13.6	28.3	1.6
West Africa (m. head)	42.8	42.2	59 5	6.4
% of SS Africa	24.0	26.0	37.7	47.4

Source: FAO (1991).

Table 12.2 Human and livestock distribution in western Africa, 1979

	Zone
	Arid	Semi-arid	Sub-humid	Humid	Total
Area (km2 million)	4.0	1.5	1.6	1.9	9.0
Agricultural population (m.)	6.9	36.1	16.1	31.1	90.2
Cattle (m. head)	9.0	21.6	6.2	3.8	40.6
Sheep (m. head)	13.2	10.1	6.7	6.0	36.0
Goats (m. head)	14.8	19.2	11.8	8.7	54.5
Ruminant TLIJ	10.8	16.7	6.2	4.3	38.0

Source: Adapted from Jahnke (1982) by McDowell and DeHaan (1986).
TLU, Tropical Livestock Unit = 250 kg livestock body weight.

Table 12.3 Livestock densities in various ecological zones of West Africa

	Zone
	Arid	Semi-arid	Sub-humid	Humid
TLU/km2	2.7	11.1	3.8	2.2
Agricultural population density (n/km2)	1.7	24.0	10.1	16.4
TLU per agricultural capita	2.5	0.5	0.4	0.1

Source: McDowell and DeHaan (1986).
TLU, Tropical Livestock Unit = 250 kg livestock body weight.

The role of monogastric food animals - poultry and swine in particular - in increased animal production potential in Sub-Saharan Africa cannot be underestimated. These animals compete with human beings for available grain, especially maize and sorghum, which are the staple food of the African peoples. However, these species can have greater meat and egg turnover in a relatively short time. Although they are intensively raised on restricted land areas, their contribution to environmental problems can be great. Air pollution owing to odour from pig and poultry houses can be a nuisance to nearby inhabitants. Sustainability of productive capacity of these animals is more easily accomplished, especially with modern trends in housing and feed technologies. Recycling of manure by spreading it on arable cropland ensures increased crop production at reasonable cost as well as environmental conservation.

The land resource, climate, and production systems

Large areas of African soils are said to be fragile and are classified as of low productive capacity in many countries within the continent. Most of the available land for agricultural production is located within fragile and ecologically sensitive regions, e.g. tropical rain forest, arid savannas, and the drought-prone Sahel, where a large proportion of the cultivated area is not compatible with sustainable agriculture. Land-use systems are usually based on incomplete knowledge of the status of the land resources of the various areas (Anande-Kur 1992). These factors must be borne in mind because knowledge and information about the land resources of a given ecosystem for a particular production - arable or livestock - are essential, as can be seen when related to the stocking density and effect on the environment.

For the purpose of this paper, I am more concerned with the ecological and agro-climatic zones in Sub-Saharan Africa as they relate to livestock enterprises and to the sustainability of all production systems.

The ecological zone classification is based on the number of growing days, i.e. days with rainfall. Thus the arid zone has 0-90 days of rainfall, the semi-arid zone has 90-180 days, the sub-humid zone has 180-270 days, and the humid zone has rainfall for over 270 days annually (McDowell and DeHaan 1986). It is the agro-ecological zones that determine both crop and livestock production in a given zone. The intensity, frequency, and distribution of rainfall influence biomass production in a given area, and hence are a determinant factor in the carrying capacity of the land for the purpose of raising livestock. In general, the majority of ruminants in Sub-Saharan Africa are raised on range-land where feed resources are mostly naturally growing grasses and legumes but with occasional supplementation with leaves of shrubs and trees. The husbandry systems are either nomadic, semi-nomadic, or settled. Stock owners with large herds often practice full pastoralism, while those who are agro-pastoralists often have small herds and are sedentary or settled. The global grazing habit of a large number of domestic ruminants has a detrimental effect on the environment, especially as the stocking density can be very high in marginal grazing areas (table 12.3). Because of the high stocking density and fewer watering points in these zones, erosion due to constant trampling around water points can be an added detrimental effect of overgrazing.

The effect of seasonality on ruminant livestock production is also very important. In the mid wet season, forage biomass is higher in quality and quantity, with crude protein up to 9 per cent in most of the native grasses. Natural grasses and legumes are rich and highly digestible at this period. As the dry season sets in, the protein level drops and the roughage quantity increases. There is an increase in lignin content and voluntary intake decreases. This is a poor feed resource, resulting in weight loss and decreased fertility and milk yield for up to 4-5 months of the year. The severity and duration of low-quality feed differ from one country to the other within the region. To worsen the ecology and its available food resources further, there is widespread annual burning of native grasslands, thereby drastically reducing the amount of forage on offer. Indeed, it has been observed that a combination of these factors - low-quality roughage and bush burning, which reduce the biomass available in quantity and quality - could lead to weight losses ranging from 300 to 400 g per head per day for cattle (Zemmelink 1974) and up to 15 per cent of body weight in sheep (Otchere et al. 1977).

In the arid zone, nomadism and transhumant systems of livestock production prevail. In these systems, high mobility for global grazing habit is the most efficient adaptation to the erratic rainfall. Migration from one area to another in search of good quality and quantity of feed and water is the rule. Transhumant or semi-nomadic systems have a home base, although they too are very mobile, with the majority of animals and the family away for several months and only 2-6 lactating cows left at the base to provide milk for sale and for the utilization of the aged parents left behind. Feed from crop residue provides the main energy source during and shortly after harvesting periods.

In all the zones, the main constraints on feed resources are the destruction of perennial tree cover for firewood, bush fires caused by hunters and livestock rearers, and overgrazing. These man-made constraints often lead to serious degradation of the range resources and in some cases to an irreversible process of desertification, especially in the Sahel zone. The sub-humid zone (SHZ) has a high potential for ruminant production because of the high rainfall and vast land area for forage production. In Nigeria, the SHZ contains only 19.59 per cent of the total national livestock units (Otchere and Nuru 1988). This low percentage of TLU in the Nigerian SHZ is attributed partly to tse-tse infestation and high humidity.

The effect of government policy on livestock production

In a number of countries, Nigeria in particular, there are governmental policies on livestock production as well as on the environment. On livestock, the government is concerned with the grazing rights of stock owners in forest areas. The Grazing Reserve Law of 1964 in Nigeria is a good example. Shelter belts have been created to prevent desert encroachment. Federal or national environmental protection agencies have been set up by some governments within the region. A lot more emphasis is, however, placed on environmental pollution from oil spillage and on drought prevention rather than on natural herbage resource conservation. In many countries, the land tenure system is a major constraint on range conservation or increased production. Policies on the land tenure system and land use are mostly to the advantage of city dwellers and a few enlightened farmers. In many countries, the laws are hardly obeyed and people (hunters, etc.) are rarely penalized. In order to achieve their objective, such laws and regulations must be not only technically sound but also socially acceptable.

Suggested solutions

It can be seen that the present livestock production, based on global grazing husbandry systems, ecological destruction through bush fires, and overgrazing due to high stocking density in areas where feed or water resources cannot support the number of animals, does not augur well for present and future productivity and sustainability.

What then are the solutions to ensure sustenance of the ecosystem and its herbage and tree shrubs cover and of the grazing livestock species for the future economic development of Sub-Saharan Africa?

Livestock production is still very much based on traditional systems in Sub-Saharan Africa, even in such agriculturally advanced countries as Nigeria, Zimbabwe, or Egypt. One would have thought that, with a large number of livestock research institutions and faculties of agriculture and veterinary medicine in the region, a newer and more modern approach to livestock enterprise would have provided the answer for future productivity and the sustainability of both animals and the environment. It is true that old habits die hard and, therefore, the traditional herding system will continue in many African countries.

It will not be possible drastically to change the cultural and socioeconomic status of the livestock producers for at least another decade. It has, however, been shown that their production systems are more efficient in terms of livestock product yield per animal per unit area, probably because of their husbandry knowledge and complete devotion to their vocation. Large-scale farms with modern techniques of production are not the only way to sustain productivity. They are too capital and labour intensive to guarantee a profit compared with the low-input systems of traditional owners. A lot of large-scale livestock and arable farmers have failed in many countries, Nigeria being a good example. Indeed, it has been shown that in Zimbabwe, Botswana, Kenya, and Mali the contribution of communal livestock production to the national animal protein yield is greater than that from commercial ranching enterprises in terms of kg of protein production per hectare per year (Barrett 1992). For these and other reasons, our attention must be primarily focused on how to improve the traditional systems, to introduce simple and adaptable innovations and techniques to enhance productivity and yet protect the environment from being abused to the extent of irreversible degradation.

Suggested solutions for sustaining the productivity of both the livestock and plant species for future development are therefore centred on the following strategies:

1. improved animal genetic resources to meet future needs;
2. improved nutrition;
3. improved management;
4. government policies and commitments;
5. active participation by the private sector.

Improved animal genetic make-up

Modern ideas about animal production are mostly based on: the use of big-engineering to improve on the genetics of various animal species for higher output, embryo transfer, and immuno-genetics; artificial insemination and cross-breeding for quick genetic gain in heterosis; improvement of reproductive efficiency through the use of hormones and drugs to improve fertility rates. Developments in breeding animals with increased resistance to diseases and pests as well as in animal health and disease control through vaccine production are major contributions. Recombinant DNA technology has of recent years offered remarkable opportunities for restructuring animal phenotypes and ability to withstand viral and bacterial diseases. Cross-breds, if so adopted, would yield more meat (through faster growth) and higher milk output in a relatively short time. The goal of all these techniques is to produce a biologically efficient animal species for each ecosystem. However useful these techniques are, they are too advanced to be used by the present-day resource-poor subsistence farmers in Sub-Saharan Africa, but could be of advantage in future to conserve the ecosystem and yet increase livestock production to meet the needs of the year 2000. For the next decade, emphasis should be on animal health through effective control of "economic diseases" such as gastroenteritis due to helminth parasites, streptothricosis, trypanosomiasis, and other chronic diseases that give rise to wastage owing to abortion, infertility, stillbirths, and unthriftiness, and even deaths.

Improved nutrition

Improved nutrition is the key factor. One way of achieving it is through increased crop yields, because grains and tubers are used to supplement natural grasses. Other methods are: effective management and utilization of natural pastures; feed resources conservation; and use of arable crop wastes.

At present, the global grazing orbit is declining owing to physical development (roads, new HQs, etc.) and the expansion of cultivated land as a result of large agricultural schemes. Therefore, better and more efficient management of range land is essential, e.g. controlled grazing, controlled stocking density, avoidance of bush fires, range reseeding, and water supply.

In order to conserve feed resources, silage and hay could be made from high-quality grass and legumes, and agricultural crop residues such as groundnut and cowpea tops could be conserved when the nutritive value of the plants used is high. Unfortunately, the inputs for such technology (tractors, bailers, etc.) are hard to come by for many peasant livestock farmers.

Within the past two decades, the mechanization of agriculture for crop production has contributed immensely to increases in cereal crop production and therefore in crop residues. However, it must be noted that mechanized farming has also physically contributed to soil degradation, resulting in deterioration of the soil structure and compaction of the subsoil (Anande-Kur 1992). These effects in themselves render the soils prone to erosion. The integration of livestock and crop production systems on a given land area can improve soil fertility through the output of organic manure by the animals and the more effective utilization of crop residues.

The utilization of crop residues for increased animal protein production has received greater research attention within the past decade because of the higher quantities of crop residue, especially from sorghum, maize, and millet, and partly because of the astronomical increase in the prices of agricultural by-products such as wheat and maize offal residue used for livestock feed, groundnut and cotton seed cake, and brewers dried grain. The importance of crop residue in the dry season feeding of ruminants in the Northern Guinea Savannah has long been recognized. Van Raay and de Leeuw (1971) estimated that crop residue grazing accounts for 85 per cent of total grazing time from the harvest period in December, declining to 40 per cent in February in the Sudan Sahel zone of Nigeria. Alhassan (1985) estimated that for every kg of grain harvested, there are 4 kg dry matter of straw from sorghum, 8 kg from millet, and 4 kg from maize straw. From table 12.4 it can be seen that approximately 16.4 million metric tonnes of sorghum straw and 23.2 million metric tonnes of millet straw were available in Nigeria in 1980/81 from 6.1 million hectares of sorghum and 4.5 million hectares of millet, respectively. This may apply to other countries in Sub-Saharan Africa where these crops are grown on a large scale. By treating this straw with non-protein nitrogen sources or chemicals (e.g. urea, ammonia, and sodium hydroxide) the lignin content will be degraded and the feed value and palatability enhanced. If animal feed is supplied in this way, further destruction of the ecosystem by way of bush fires for early grass growth and overgrazing when feed resource is scanty can be prevented or minimized. Here again, education of the stock rearers about the need to settle and adopt such simple technologies is essential. Other agricultural by-products with great potential for animal feed include sugarcane tops, molasses, bagasse, discarded cocoa beans, pineapple tops, and other rejects.

Table 12.4 Estimated areu sown to sorghum and millet and their grain and straw producffon for venous cropping years

Year	Sorghum			Millet
	Area	Grain production	Estimated straw	Area	Grain production	Estimated straw
	(ha m.)	(m.t)	(m.t)	(ha m)	(m.t.)	(m.t.)
1964/65	5.6	4.2	16.8	4.4	2.7	21.6
1969/70	5.8	4.3	17.2	4.2	3.2	25.6
1974/75	4.8	3.9	15.6	4.0	2.6	20.8
1980/81	6.1	4.1	16.4	4.5	2.9	23.2

Source: Nuru (1986).

It can be seen that, for optimum resource usage, there is an urgent need for an integrated approach to livestock development for increased product availability at reasonable or affordable prices and enhanced natural resource management and conservation.

Similarly, the use of microbes has greatly enhanced our knowledge about the production and utilization of better nutrients to feed various species of animals for a higher output of meat, milk, and milk products. In addition, modern trends in production make use of anabolic steroids - a combination of progesterones, oestrogen, testosterone, and zeasolone (plant origin) - as feed additives to promote faster growth and therefore higher output; growth hormones to increase milk production in lactating cows; and ionospheres (antibiotics) and coccidiostats in poultry. These drugs are mentioned only in passing here, because the level of education, socio-economic status, and acceptance of these new techniques by the majority of livestock producers cannot at present be guaranteed. Only a few enlightened farmers in southern Africa are able to use these technologies. More appropriate and simple technological innovations therefore need greater emphasis.

Improved management techniques

Sedentarization

Change from a free-range production system to an acceptable marketoriented and sedentary system could be considered. Most of the destruction of ecosystems is due to bush burning, overgrazing, and lack of adequate water points. A more sedentary husbandry system with higher input and higher output could be desirable in some agroecological areas. This would not be easy in the arid zone, but it would be possible in the semi-arid and sub-humid zones. In the arid zones, a reduction of livestock numbers in keeping with the carrying capacity of the land is desirable. Agro-pastoralism is a solution in some areas where there is adequate rainfall. This is the emerging trend in the sub-humid zone of Nigeria, where more and more pastoralists are settling (ILCA 1979; Otchere et al. 1985). In this way, the concept of integrated farming systems can develop to great advantage. In the Congo, and other densely forested countries, the use of typanotolerant breeds of animals is now more emphasized. These animal species are not only adapted to the environment but also more productive in such areas. It must be noted, however, that sedentarization and its acknowledged benefits can be achieved only through a dynamic and workable land tenure system that is the responsibility of the government.

Agro-forestry

According to Harrison (1987), forestry has been considered separately from agriculture and livestock. Foresters view farmers and herders as vandals and destroyers of forests, while peasants see foresters as policemen who exclude them from land that was traditionally theirs to control and use. Farmers view tree planting as an alien activity carried out by unpopular professionals. Forestry nevertheless has a crucial role in farming and pastoralism in Africa. There is a need to integrate forestry fully into crop and livestock production in order to sustain agriculture in a stable ecosystem in the future. The Grazing Reserve Law in Nigeria is worthy of emulation by other countries. Suitable trees will provide fodder for animals at the end of the dry season and the beginning of the rains when feed is scarce. The most crucial role of appropriate forest trees would be the recycling of soil nutrients in an environment in which heavy rains leach nutrients below the reach of crop roots and the maintenance of soil organic matter in an environment in which high temperatures break down organic matter very quickly. A promising approach to agro-forestry to sustain crop and livestock production is alley farming. Suitable multi-purpose trees that provide abundant fodder or mulch from their leaves, fuelwood and stakes from their stems, as well as the ability to fix nitrogen are greatly recommended. At the moment, trees such as Leucaena leucocephala, Gliricidia septum, and Sesbania seban, among others, have been found suitable. There is, however, the need to increase the number of species that meet the requirements.

Pasture establishment

With the current increase in crop production through massive landclearing in many countries in Sub-Saharan African, coupled with the growth of population and hence the physical development of more and larger towns and cities (urbanization), the land-use pattern is constantly changing and less land is available for crop and livestock production.

Intensive production systems and the use of crop residues and agricultural by-products are thus further emphasized. Because of the limiting factors on global grazing, which are even more likely to be a problem in the year 2000 if livestock and human population growth are not restrained, the need arises for sedentarization and pasture establishment if there is to be enough animal protein and at the same time the natural ecosystem is to be conserved. Technically, scientists have developed suitable pasture plants to meet the variations of the agro-ecological zones in Sub-Saharan Africa. The grasses and legumes required include Digitaria spp., Buffel grass, Guinea and Rhodes grasses, together with Stylosanthes, Centrosema, and other varieties of legumes. It will require social and cultural changes amongst the nomadic and livestock owners if they are to adopt the technologies that have been developed and to treat livestock ventures as viable commercial enterprises not just a way of life. In this respect, several African governments have a lot to do as regards land tenure systems and the provision of assistance in the acquisition of infrastructure and credit facilities for a profitable future livestock industry.

As part of the new technology in animal husbandry, improved pastures produce more dry matter of high nutritive value and lead to greater animal productivity than do native pastures. To date, the traditional African livestock farmer has yet to adopt these new techniques. Throughout Sub-Saharan Africa, grazing land is communal; only a few private ownerships exist. Improvement of the range by individual stockowners by oversowing with legumes and by fertilization is not advantageous because grazing areas are for communal usage.

There must be more emphasis on the training of range and pasture specialists in order to achieve success in range improvement and conservation and in pasture establishment and effective utilization, and also to prevent further range degradation and to ensure increased livestock productivity.

Government policies and commitments

Government policies and programmes to assist herdspeople and the millions of people engaged in livestock enterprise need to take cognizance of the following:

(a) The land tenure system must be revised in some countries to make it easier for those who really need land to obtain it. The need to instill pride of ownership and willingness to invest in development is crucial because communal grazing is free and therefore unattractive for commercial livestock enterprise.

(b) Nomadic education as presently carried out in Nigeria is encouraging and worth emulating by other countries.

(c) The supply of sufficient manpower/experts, e.g. animal scientists, range managers, and technical staff, is essential. Most African universities are non-starters in the production of such specialists.

(d) Regulatory control of herd size and distribution to achieve ecological balance and avoid overgrazing needs policy attention. The encouragement of herd owners to move to the sub-humid zone in Nigeria, which is rich in feed resources, is a very slowly developing programme.

(e) Greater incentives to producers - marketing, credit facilities, technical supervision, subsidized inputs, etc. - are essential.

Active participation by the private sector

Private sector participation in the primary production of livestock is highly desirable if the necessary output of livestock products is to be achieved in the future. Through this sector, environmental degradation can be minimized and increased productivity of livestock products ensured. So far, only in Zimbabwe, Botswana, Kenya, and South Africa are people engaged in modern commercial livestock production. The need to invest in the industry as a high-potential economic enterprise cannot be overemphasized if the future is to be safeguarded.

Summary and conclusions

The demand for food of animal origin is growing much faster than production because of better health education, higher income per capita, and ever-increasing population growth. Yet, owing to the application of Structural Adjustment Programmes, many African countries are poorer than before and livestock products are beyond the reach of the ordinary person. Many governments in Sub-Saharan Africa will face serious problems in terms of food self-sufficiency and food security if immediate and adequate measures for sustainability are not taken.

The two most important resource bases in livestock production are the animals and the range land on which they depend for survival. The genetics of the various species of animals and plants and their interaction within a given ecological zone form the basis of their productiveness or otherwise. The ability to maintain the pace of economic development from these resource bases (since they are governed by external factors, e.g. climate, social, cultural, and economic status of herdspeople) is the focus of the concept of sustainability. However, for any given system one may wish to sustain more than one aspect of the system. For example, in livestock systems, genetic considerations may be just as important in the tropical environment as the feed resource base, in which case conflict can arise. Again, the concept of sustainability without consideration of social objectives or goals is meaningless in terms of future economic development. The herd owners' social objectives may not tally with the government policy objective in that the herd owners may be more interested in maximizing the numbers of their stock whereas the government objective may be sedentarization of the herd owners in order to be able to increase the productivity of the animal per unit area using available technologies in animal husbandry, including nutrition and herd health management. Sustaining a given subset of a system therefore needs to be taken more seriously while thinking of overall future economic development gains.

Ruminants have a greater effect on ecosystems than other animal species. They are numerous and provide substantial quantities of animal protein. However, their production is based on age-old husbandry systems, which need to be gradually modified in order to meet the needs of consumers. A reduction of animal numbers in accordance with the resource capability of the land is essential. The various governments in Sub-Saharan Africa must try to achieve this through legislation and inducement packages. In addition, the sedentarization of nomads and the acquisition of land (i.e. a change in land tenure systems) can greatly increase the adaptation and use of new techniques in animal production systems.

The present poor system of livestock production of the majority of herd/flock owners should not be a deterrent to exploring future possibilities. In this context, therefore, one could stress the need to "domesticate" the environment so that it can cope with the production effort, especially for monogastrics. The alleviation of environmental stress through genetic improvement, hormonal regulation, feed intake, and control will be an important consideration for future needs.

Research into optimum environments for livestock will need to be addressed; for example, poultry houses with relative humidity, temperature, etc. controlled to make them conducive to rearing have led to higher output in Europe, the USA, and other countries. Comfort, productivity, and the economics of poultry and swine production will be the rule rather than the exception even in tropical environments. These are to be achieved through environmental control and animal welfare considerations.

Owing to space constraints, I have not considered the role of wild life in the preservation of ecosystems in this paper. They form part of Africa's cherished biodiversity and their significant role in the supply of bush meat, especially to rural people, needs no emphasis. However, with intensive hunting for game, they are declining in number, and the present number of herbivorous species is not a threat to the ecosystem. Destruction by bush fire and the cutting down of young and old trees for firewood or the clearing of dense natural forests for agriculture pose more threat to the system and should be regulated for future animal protein production.

Government assistance through research and the development of specialist skills, e.g. range management, pasture expertise, and animal science, is of paramount importance to ensure future economic growth and development in the livestock sector if Sub-Saharan Africa is to meet the challenges of the future.

References

Alhassan, W. S. 1985. The advances in ruminant nutrition and their application to the utilization of poor quality forage. Paper presented at the IOth annual meeting of the Nigeria Society of Animal Production, University of Ife, Nigeria.

Anande-Kur, S. 1992. Land management and problems in large-scale farming in Nigeria. Paper presented at a conference on Large Scale Agriculture, Abeokuta.

Barrett, J. C. 1992. The Economic Role of Cattle in Communal Farming Systems in Zimbabwe. Pastoral Development Network Paper 32b, March.

FAO (Food and Agriculture Organization of the United Nations). 1991. Production Yearbook 1990, vo]. 44.

Harrison, P. 1987. The Greening of Africa. Breaking Through in the Battle for Land and Food. London: Paladin Griffon.

ILCA. 1979. Livestock Production in the Subhumid Zone of West Africa: A Regional Review. ILCA Systems Study no. 2. Addis Ababa, Ethiopia: International Livestock Centre for Africa.

Jahnke, H. E. 1982. Livestock Production Systems and Livestock Development in Tropical Africa. Kiel: Kiefer Wissenschafts Verlag and Vauk.

McDowell, R. E. and C. DeHaan. 1986. West African Agricultural Research Review: Livestock Research.

Nuru, S. 1982. Problems and prospects of the Nigerian beef industry. In: O. A. Osinowo (ed.), Proceedings of the National Conference on Beef Production. Kaduna, Nigeria, pp. 12- 43.

---- 1983. Effective harnessing of Nigeria's agricultural resources: The case for livestock production sub-sector. Annual Conference of the Agric. Society of Nigeria, Ilorin.

---- 1986. The role of research in increasing food production in Africa. In: B. Webster, C. Valverde, and A. Fletcher (eds.), The impact of Research on Narional Agricultural Development. A Report on the 7st International Meeting of National Agricultural Research Systems. Brasilia, Brazil, pp. 53 63.

Otchere, E. O. and S. Nuru. 1988. Ruminant livestock production and feed resources in the subhumid zone in Nigeria: Constraints and perspectives. Journal of Animal Research 8(2): 147 168.

Otchere, E. O., C. B. M. Dadgie, D. A. Ayebo, and K. E. Erbynn. 1977. Response of grazing sheep to rice straw or cassava pellets fortified with urea and molasses as supplemented feed. Ghana Journal of Agricultural Science 10: 61 66.

Otchere, E. O., H. U. Ahmed, Y. M. Adesipe, M. S. Kallah, N. Mzamane, T. K. Adenowo, E. K. Bawa, S. A. A. Olorunju, A. A. Voh Jr., E. A. Lufadeju, and S. T. Balogun. 1985. Livestock production among pastoralists in Giwa District. Preliminary report of the Livestock System Research Project, NAPRI, Nigeria (unpublished).

Van Raay, H. G. T. and P. N. de Leeuw. 1971. The importance of crop residue as fodder: A resource analysis in Katsina province, Nigeria. Samaru Research Bulletin no. 139, Institute for Agricultural Research Samaru, Zaria.

---- 1974. Fodder Resources and Grazing Management in a Savanna Environment: An Ecosystem Approach. Occasional Paper no. 45. The Hague: Institute of Social Studies.

Zemmelink, G. 1974. Utilization of poor quality roughages in the Northern Guinea Savanna zone. In: J. K. Loosli, V. A. Oyenuga, and G. M. Babatunde (eds.), Animal Production in the Tropics. Ibadan, Nigeria: Heinemann.

(introduction...)

Introduction
Population and environmental concerns
The primary energy sector in Sub-Saharan Africa
Problems of the energy sector in Sub-Saharan Africa
The socio-economic implications of the fuelwood crisis
Strategies to combst the fuelwood crisis
New and renewable energy development
Conclusion
References

 

Elizabeth Ardayfio-Schandorf

Introduction

At the core of the question of the sustainable development of SubSaharan Africa (SSA) lies the problem of development itself. Without development there is the possibility that SSA's problems will multiply. Since the 1960s its gross domestic product (GDP) has declined steadily. Higher oil prices, fluctuating agricultural commodity prices, and a lack of adequate response strategies have contributed to aggravate this situation. Excessive borrowing from international financial institutions provided funds to support infrastructural development, but the inability of SSA to service these loans has resulted in the region's present debt crisis. Other factors such as the drought of the 1980s severely affected the food and energy supplies of most countries. Further decline in these countries may tend to undermine growth in the economy. Should population growth occur without development, SSA will be compelled to exploit its resources on a non-renewable basis, thus accelerating environmental deterioration. For effective development, SSA should aim at a type of development that is sustainable.

In this connection, an important element in the developmental system is the complex issue of energy.

The countries in SSA are rich in modern energy resources. A few have large oil and natural gas reserves, some have coal, and several have hydroelectric power. Albeit, the rate of consumption of these resources is limited, per capita consumption being the lowest in the world. The main commercial energy resources consumed in SSA are petroleum (41 per cent), natural gas (14 per cent), hydroelectricity (10 per cent), and coal (35 per cent). In the total resources, including traditional fuels, wood fuel is dominant (Ardayfio 1986). All these energy forms have their environmental effect. Contemporary biomass fuel use results in deforestation and land degradation, which is associated with non-sustainable use of land resources and environment. Air pollution is also linked with the use of coal, oil, gas, and water, and with solid waste problems. Policies relating to institutions and investments are needed to improve the energy situation and reduce the environmental impact.

Hence this paper seeks to appraise the extent of the energy problem in Sub-Saharan Africa with special reference to the fuelwood crisis. The problems of the energy sector in the rural and urban areas are considered, while subsequent sections are devoted to the socioeconomic implications of the fuelwood crisis and the strategies that have so far been adopted to combat the crisis. Finally, the development of new and renewable energy is discussed before the conclusion.

Population and environmental concerns

The population of Sub-Saharan Africa is growing by leaps and bounds (3 per cent per annum), reaching over 459 million in 1990 (World Bank 1992) in spite of family planning measures to bring it under control. With a fast population growth rate, people are unable to feed themselves. Meanwhile energy demand is increasing with the rise in population. With increased urbanization and industrialization the situation is worsening as more energy is needed. At the same time, an increase in the demand for petroleum for food production and modernization is leading to an economic crisis. The cost of imports has risen and the value of exports has fallen. More cash crops have to be produced to provide foreign exchange. Meanwhile, farmers and nation-states in general are impoverished and indebted because they have to produce more for less cash. With the shortening of the follow period marginal lands have to be exploited, leading to environmental crisis with rising economic and environmental costs of production (fig. 13.1). High fertility rates and a high percentage of child-bearing women are contributing to the high population growth rates. The issue at stake here is the distribution of the population and its influence on the existing resources of the region. Urbanization rates are even higher (5.6 per cent), though in many countries economic growth has been slow over the past few decades.

The upsurge of population growth has short- and long-term consequences for the existing forest resource base, land use, and fuelwood production. The economic crisis, with its concomitant high rates of unemployment and very low incomes, has encouraged the use of fuelwood in most African cities (fig. 13.1). These urban centres have become, as it were, a lucrative market for fuelwood because it seems to be relatively available and cheaper than modern fuels, which hitherto have not proved a viable alternative in either rural or urban areas.

With growing population pressure on land use, a fuelwood gap is created, putting more pressure on the producing rural areas. Ultimately it is not only the sustainability of the environment that is at stake but the very survival of the urban poor and rural people, with women being the worst victims.

Though the countries of SSA may have divergent political systems and cultures, in broad terms they seem to have a common feature in so far as energy is concerned. They are literally being squeezed in a common energy problem. On the one hand, there is a heavy reliance on imported petroleum for the commercial sector, making petroleum shortages a chronic problem. On the other hand, there is a growing shortage of fuelwood in the predominant traditional sector and acute scarcity in some subregions.

The fuelwood crisis, as the "other energy crisis" is called, began to emerge during the oil crisis of the 1970s and has been aggravated by agricultural policies that aim at making African countries selfsufficient in food production (Eckholm et al. 1984). This has been achieved at the expense of existing forest lands, which are the main sources for fuelwood. National programmes tend to overlook this relationship between food and forest, so that the focus has been either wood or forest. This implies that wood energy is not being exploited in a manner that is sustainable in African countries. It appears that a more acceptable means for safe and sustainable energy production is yet to be found. Before this can be achieved, a good understanding of the African energy situation needs to be established as a basis for formulating a sustainable energy agenda.

Fig. 13.1 The crises of sustainability in Sub-Saharan Africa

According to Gamser (1980), little is known about the dependence of poor people in Africa on the use of forest resources for meeting their energy and subsistence needs. The measures needed to develop energy resources to ensure that rural interests can be served are also not well known. Gamser claims that there is not sufficient empirical understanding of the ecologically diverse lands involved in the tropical forest energy crisis. Neither have forest surveys provided adequate data on the dynamics of forest energy. He therefore calls for a concerted effort on the part of the international community to react positively to the shortfall in the existing data on forest energy production and consumption. At the moment most wood energy statistics, including those of the Food and Agriculture Organization (FAO), are based on estimates or unofficial sources, and this has been rather a weakness as regards knowledge about traditional energy. However, studies undertaken since the 1970s reveal the vulnerability of African countries so far as energy resources are concerned.

Although Africa accounts for 12 per cent of the global population, it consumes only 4 per cent of global energy. Besides, 40 per cent of its energy consumption is mainly in the form of biomass and it consumes no less than 40 per cent of this resource. On the global scale, the proportion of biomass in its total energy consumption is 6 per cent (see tables 13.1 and 13.2).

The rate of consumption varies within Africa when compared with other continents. In the Republic of South Africa, for example, out of the annual per capita consumption of 95GJ, only 5 per cent is biomass; in North Africa it is 11 per cent out of 34GJ. In Sub-Saharan Africa by contrast, out of the minimal per capita consumption of only 15GJ, 73 per cent is biomass (FAO 1987).

In the subregions of Africa the fuelwood situation may be determined by the political economy, the ecology, the geography, the demography, and the culture. Thus the fuelwood situation varies from the Sahel across humid West Africa, through Sudan, Kenya, and the SADCC countries.2 However, within each of these countries, two energy crises, of petroleum and of fuelwood, are experienced.

The primary energy sector in Sub-Saharan Africa

Although SSA is rich in modern energy resources, some of these are underexplored. The energy potential is expressed in the abundance

Table 13.1 Estimated energy consumption in Africa, 1990

Fuel(a)	World Million		Africa Million		Africa as % of world
	TOE	EJ	TOE	EJ
Gas	1,610	68.8	25	1.1	-
0il	2,740	117.1	85	3.6	-
Coal	3,180	135.9	86	3.7	-
Hydro(b)	630	26.9	14	0.6	-
Subtotal	8,160	348.7	210	9.0	2.6
Biomass	600	25.6	140	6.0	23.4
Total	8,760	374.3	350	15.0	4.0
Population (million)	5,300		650		12.3

Source: United Nations (1990).
a. TOE = tons of oil equivalent.
EJ = exajoules = 10¹⁸J.
b. Primary energy equivalent.

Table 13.2 Estimated energy consumption in Africa by region, 1990

Fuel	North Africa		Sub-Sahara excl. R.S.A.		Republic of South Africa
	Million TOE	EJ	Million TOE	EJ	Million TOE	EJ
Non-biomass fuels	80	3.4	47	2.0	83	3.6
Biomass fuels	10	0.4	126	5.4	4	0.2
Total	90	3.8	173	7.4	87	3.8
Percentage	26%		49%		25%
Population (million)	114	(17%)	497	(77%)	39	(6%)

Source: United Nations (1990).

Within Sub-Sabaran Africa only five countries account for almost all the oil produced - Nigeria, Angola, Gabon, Congo, and the Central African Republic (in descending order of output in 1991). The greater proportion is exported outside the region, even though petroleum is needed internally. Nigeria alone accounts for about three-quarters of the OPEC oil regulated quotas. On the whole, the total petroleum consumed is below 25 per cent of the total production (figs. 13.2 and 13.3).

Natural gas reserves on the continent are enormous and it is observed that the current reserves outweigh petroleum reserves if the current rate of production is taken into consideration. Coal reserves, which are more concentrated in the south, are expected to last for about 300 years. The growth rate of coal production has been slow, partly owing to greater reliance on petroleum for energy and to infrastructural and environmental problems.

Unlike coal, hydropower production is more widespread and has been increasing. It grew nearly four-fold between 1950 and 1988. Even at this growth rate, only 4 per cent of this power potential is exploited. Initial investment in production, environmental concerns, as well as old equipment and recurrent drought, have contributed to slowing down the growth of this power sector. Geothermal energy is utilized mainly in East Africa, and the possibility of its development needs to be explored for use elsewhere in SSA. The same goes for the production and supply of renewable energy sources. In these circumstances, wood fuels have become the predominant source of energy in the region.

Problems of the energy sector in Sub-Saharan Africa

Before the oil crisis in the 1970s, consumption of petroleum and its related products increased because oil was cheap and considered an infinite resource. The advanced industrialized countries developed a consumption infrastructure in the industrial and transport sectors. This meant that demand for petroleum was relatively inelastic. SubSaharan Africa unfortunately developed along these same lines, making it more vulnerable in the oil crisis.

The establishment of the Organization of Petroleum Exporting Countries (OPEC), which includes African countries such as Gabon, Nigeria, and Angola, was in response to the inelastic consumption pattern set up by the West in an effort to restrict oil output and to raise prices. Considering the high industrial development and the financial resources available, the West made attempts to move away from petroleum to alternative fuels. Such a move has not been possible in the non-oil-producing countries of Africa, where oil consumption in the energy balance is small and imports very high. For instance, Ghana spends 13 per cent of its foreign exchange on petroleum imports, but this rises to over 20 per cent in Tanzania and Kenya, and more than 40 per cent in Mozambique.

Fig. 13.2 African energy in relation to world production of crude petroleum and electricity (quantities in '000 metric tons of coal equivalent) (Source: based on United Nations 1990)

Fig. 13.3 African energy in relaffon to world consumption of crude petroleum and electricity (quantities in '000 metric tons of coal equivalent) (Source: based on United Nations 1990)

In spite of these huge financial burdens, the direct benefits that accrue from these exorbitant petroleum imports scarcely benefit the rural people. As O'Keefe (1990) remarks, even the recent fall in oil prices may be unlikely to ease the various rationing systems that operate in most non-oil-producing countries in Sub-Saharan Africa.

Because the rural and urban poor cannot afford high-priced petroleum products they have to depend on fuelwood in the various socioeconomic sectors. We therefore find in Sub-Saharan Africa a "paradox" of the wood-fuel situation: a situation of abundant wood-fuel resources in some countries and an acute shortage in certain areas as found in countries such as Ghana and Angola.

In 1981, the FAO undertook a global survey in order to determine fuelwood supplies and demand for them in developing countries such as Africa in 1980 and the year 2000. This was supposed to be one of its contributions to the United Nations Conference on New and Renewable Sources of Energy. Because there was a paucity of source material, the data were based on projections from the early 1980s, but the results present a reasonable picture of the status of fuelwood in Africa. Four major categories of the fuelwood situation were identified:

1. Areas where there has been overexploitation of biomass to the extent that there is fuelwood shortage.

2. Areas where fuelwood demand is in excess of sustainable supply -referred to as "crisis regions."

3. Areas where population growth is likely to give rise to crisis in the foreseeable future - categorized as satisfactory. In this regard the situation in the Sudano-Sahelian region is critical because acute shortages are expected, especially in the rapidly growing periurban areas. This is occurring because of increasing encroachment of agricultural land, and industrial, residential, and commercial developments. Bushfires and fuelwood production compounded by population expansion have also resulted in gradual depletion of wood-fuel resources on an annual basis.

4. Areas estimated to be generally free of fuelwood supply problems - the humid and semi-humid areas. Nevertheless, large urban centres such as Yaounde, Brazzaville, and Kinshasa located within the forest ecosystems are already experiencing local shortages. This is also occurring in the semi-humid areas of East Africa wherever very high population densities threaten wood-fuel resources. Communal land reserves are particularly in danger of fuelwood depletion.

As an example of the fuelwood situation in East Africa, the Kakamega District of the Western Province of Kenya can be cited. Having an area of 3,500 km2, which constitutes only 0.5 per cent of Kenya's land area, the province harbours over 6.5 per cent of the population. As one of the most populous regions of the country, its population densities are over 800 persons per km2 in localized areas. This has generated a mosaic of small fragmented farms of about 0.5 ha feeding large families of about 10. Consequently, considerable pressure has been put on the limited land to the extent that agriculture and fuel needs are severely threatened. Farmers have no viable alternatives other than to depend on their own tiny land-holding for fuelwood supplies.

Similarly, a fuelwood deficit is to be found in the small mountainous SADCC countries, where population pressure has created acute wood-fuel shortages in countries such as Malawi and Swaziland. The situation in island countries such as Madagascar is also critical, particularly in the central and western sections.

The dynamics of the fuelwood situation represent a growing crisis. Whereas, in 1980, 55 million people in Sub-Saharan Africa lived in areas where there was acute fuelwood scarcity and another 146 million lived in areas with an increasing deficit, it is estimated that by the year 2000 about 535 million people will experience a critical fuelwood deficit if exploitation continues at the current rate (United Nations 1990). Wood-fuel exploitation is not solely responsible for environmental degradation. In the forest areas of SSA, deforestation is caused to a large extent by logging and forest clearance for cultivation. Many trees are also lost as fallow periods are shortened. Generally, areas with a high rate of tree regrowth can meet the needs of a larger population than those with low growth potential. Areas with woodfuel deficits are those with low to moderate rainfall and high population densities. In areas such as the Sahel where there is very low population density and low rainfall, the demand for wood fuels has outstripped the slow growth potential of the woody plants, creating acute fuelwood problems in urban and rural areas.

Energy in rural Africa

Rural energy use in Africa is generally low, reflecting the low industrial and urban base of the African economy. The more rural and the lower the incomes of the community, the more use they make of traditional fuels. Cooking, heating, and local industrial establishments are major consumers of household energy, which is dominated by wood fuels (FRIDA 1980). On present trends it is unlikely that fuel switching will occur in the near future on a large scale. As the population expands one would expect a direct increase in fuelwood utilization.

This being the case, a "wood-fuel paradox" can be observed in operation at both local and national levels. In many African countries there is adequate forest stock for wood-fuel production. Within this apparent situation of plenty, however, specific localized wood-fuel shortages exist in western Kenya, northern Ghana, Angola, Zambia, and the Sudan. Arid and semi-arid areas have their share of scarcity just like the large deforested areas in Botswana, Lesotho, and Swaziland. The low carrying capacity of these countries means that growth is not sustainable for either agriculture or wood fuels. For example, in Zimbabwe, Chad, and Mali, advanced deforestation and soil erosion in infertile areas with poor rainfall have forced many people to migrate.

Deforestation is affecting many rural people, who have been accused of being the cause of deforestation. More often these people produce fuelwood from their own food farms, secondary forests, or fallow lands. Where trees are cleared from agricultural land, they are readily used as fuelwood. Deforestation is caused primarily by the need for fuelwood for the curing of tobacco and tea, by excessive felling of timber for domestic and export markets, by agricultural production, by urbanization, by bushfires, and, more significantly, by demand for wood fuel by urban households.

Urban fuel demand

Patterns of household energy use in urban areas are far more complex than in rural areas. As rural-urban migration opens up more avenues for the poor, it also brings about various problems with limited opportunities. Catering for the fuel needs of the poor is just one of the essential services that poor migrants have to provide in the urban area. These are services that would have been free if they were in the rural areas. As most towns in SSA are growing rapidly, urban growth is paralleled by increasing demand for energy to meet consumption needs. This is met by wood fuels. Hence it is estimated that, if the current rates of population growth continue, urban wood-fuel consumption will surpass that of rural areas in the next 20 years or so (O'Keefe 1990).

The significance of fuelwood in the urban energy balance is the limited access to alternative fuels. Fuelwood competes with other household fuels such as kerosene, liquefied petroleum gas (LPG), and electricity. The choice of fuelwood depends among other things on its cost relative to commercial alternatives, their availability and security, and supply bottlenecks. These encourage a lucrative black market in which prices are much higher than the official stated prices. The prohibitive costs tend to increase the reliance of poor women on fuelwood even if it is scarce and expensive. Besides, there is also the cost of modern cooking stoves, which is not affordable to many households that may want to switch fuels.

The available evidence indicates that urban fuelwood prices have been rapidly increasing, causing a household dilemma for poor women. In urban centres in poorer environments fuelwood prices are almost comparable to those of modern fuels. According to Leach and Mearns (1989), African cities such as Addis Ababa, Harare, Nairobi, and Abidjan are experiencing fuelwood price rises in excess of general inflation rates. Thus fuelwood prices in many large cities are increasing in real terms.

Urban demand for fuelwood is accelerating the degradation of woody vegetation. For example, in the Sudan an area of 31,000 km2 of woodland is cleared each year for fuelwood production, especially for charcoal. In certain areas the resulting scarcity has created a disastrous effect on supplies. For example, in Burkina Faso the land surrounding the city of Ouagadougou has been completely cleared of woody vegetation for 45 km in all directions (French 1978: 1-3). As a result, bulky and low-value wood fuels are transported over hundreds of kilometres to urban markets where the fuels are badly needed. Similarly in East Africa, charcoal has to be transported for about 600 km to Nairobi and its environs. In Nigeria, the long-distance haulage of fuelwood to urban centres has been an official concern since early colonial times (Cline-Cole 1985).

As more land around the towns and cities is further depleted of its remaining vegetation, a vicious cycle of soil erosion is set in motion. In extreme cases, wood fuels gradually vanish from the urban market, as in the Cape Verde islands. Judicious urban energy planning may minimize the degradation and improve the access of women and the urban poor to other energy alternatives.

The socio-economic implications of the fuelwood crisis

Generally, the economic and social consequences of fuelwood exploitation and consumption are overlooked. In Ghana, for example, cooking in the home depends on fuelwood, which is responsible for more than 75 per cent of all energy consumed in the country annually. Most small-scale industries and food-processing enterprises that women undertake depend in large part on wood fuel. This dependence on wood fuels has contributed to the growing exploitation of the country's forest. In all, about 650,000 ha of forest are destroyed every year through the carbonization of charcoal. Alarmingly, between 1974 and 1990 wood-fuel consumption increased by 50 per cent in the country (Ardayfio-Schandorf 1993). This increase mainly reflects the urban demand previously discussed.

Urban demand has, as it were, created fuelwood markets, providing job opportunities for both men and women. Men are involved in the long-distance trade in fuelwood and charcoal, and women are in small-scale fuelwood businesses focused on villages and local markets. Charcoal production is undertaken by women in towns and villages, where they run family businesses more actively during the off farming season.

Though inefficient, wood-fuel production and distribution contribute to some extent to the national balance of payments at the macro level, as foreign exchange that might have been used for the purchase of imported fuels is saved through the use of traditional fuels. This notwithstanding, poor urban women have to pay higher prices for fuelwood and charcoal owing to commercialization. In the rural areas, women and children walk long distances to produce, harvest, and transport fuelwood to their households. However, in areas where forest resources are abundant the production of fuelwood is less problematic. In areas of high population density, women spend longer hours producing fuelwood. In such areas, women collect fuelwood on their return from the farm while they do other things as well (Ardayfio-Schandorf 1981). Similarly, in the semi-arid, arid, or savanna areas with low population density where wood-fuel resources are scarce, women have to walk for longer distances to produce fuelwood.

Where these problems exist, a bigger burden is put on women, who have to make some trade-offs. Women curtail cooking time and even cut down on economic enterprises to make time for fuelwood production. The production time varies from one region to another, with walking distances ranging from about 1 to about 10 km and even more in places such as Ethiopia. The distance covered is reflected in the cost of fuelwood.

In the Sahelian countries where deforestation is severe, fuelwood costs as much as food. Even in Ghana it has been found that women in the savanna (semi-arid) regions have cut down on their cooking time and are cooking less nutritious food because of the fuelwood crisis (Ardayfio, 1986). In view of these problems, some scholars argue that the real energy crisis is women's time. However, the energy crisis goes beyond women's time. In areas where fuelwood is the only energy input for commercial activities for women, they have been forced owing to cost and non-availability of fuelwood to discontinue many economic activities. Because of this pressure, women who are involved in household fuelwood production have developed an intimate knowledge of wood species critical for fuelwood and charcoal production. This knowledge could be exploited in planning to meet improved wood-fuel supplies.

Strategies to combat the fuelwood crisis Strategies to combst the fuelwood crisis

The oil crisis in the 1970s, which raised awareness of the wood-fuel problem, set in motion various strategies for combating it (Eckholm et al. 1984). One of the initial steps that have been taken to solve this problem has been the gathering of adequate data to enhance the understanding of the crisis.

One of the earliest institutions to contribute to the debate was the United Nations University in Tokyo, which recognized the wood-fuel issue as a pressing global problem within its programme of environmental resource utilization and management. Extensive studies were carried out in south-western and northern Nigeria. Among the other institutions that developed a similar focus was the International Labour Organization, whose studies embraced Africa as well as other countries in the developing world. Further information has also been provided by the Beijer Institute of Stockholm about the SADCC countries of southern Africa.

These studies, including the more current ones that are now being undertaken by national institutions, have shed some light on the fuelwood crisis, but more information is still needed to construct a much clearer picture to replace the existing one based on projections from the 1980s. For example, the question of measurement of fuelwood is yet to be solved through further studies throughout SSA.

In the supply and demand area, strategies included a focus on village woodlots, reafforestation, and afforestation programmes based on forest management technology. In Kenya, a study indicated that afforestation programmes projected to the middle of 1985 would contribute only 5 per cent to total fuelwood demand. If such forest plantations were embarked upon in order to solve the wood-fuel problem, the effect will be marginal because the viability of some of the programmes themselves has been questionable.

In spite of this, afforestation programmes have the potential of ensuring some degree of regeneration to conserve soil and water resources around urban centres. They could also provide industrial raw materials and possibly generate export income by exporting timber. In Kenya, for instance, woodlot programmes have been successful in areas that do not have problems with land ownership. They have helped to ease pressure on the natural forest, to protect the environment, and to satisfy the fuelwood needs of the local communities concerned.

Moving to West Africa, the concept of natural forest management, which had been practiced since World War II to provide fuelwood, was revived in the Sudan savanna town of Ouagadougou. This move was made to supply wood from classified forests to meet the growing fuelwood needs. Agro-forestry is also being promoted throughout the semi-arid countries in the region, and is now practiced in most countries, including Sierra Leone. This approach could be further promoted by giving incentives to local people to grow more of their own fuel on their own farmlands and on community land. The short rotation of non-indigenous and indigenous trees for fuels, food, fodder, and other industrial products would be beneficial to most villagers.

The policy implications of these programmes could be far-reaching. Owing to the environmental costs and benefits associated with forestry/energy projects, many countries in Africa are adopting policies that will also modify current energy consumption patterns. Energy policies are being enforced by the appropriate ministries, such as the Ministry of Energy in Ghana, the National Electric Power Authority of Nigeria, and the National Energy Administration of the Sudan. Some of these policies try to improve efficiency by narrowing the fuel energy production ratio. Energy-saving devices, including improved charcoal stoves, have been introduced to replace the traditional stove gradually. Some of these stoves could save up to 50 per cent of fuelwood demand and reduce the energy bill of women in urban centres (FAO 1987).

Other policies have focused on reducing national demand through appropriate pricing policies, improving the current supply of fuelwood through a more efficient charcoal-manufacturing process, and reducing fuelwood consumption patterns by increasing the use of conventional fuels such as petroleum and its by-products. Attempts have also been made to increase the supply and use of new and renewable energy sources.

New and renewable energy development

Many Sub-Saharan African countries have great potential for the development of hydropower, which is the major source of electricity production (70 per cent). The rest comes from thermal plants, which are fuelled by oil or in some countries by coal. Despite this potential, electricity represents only 10 per cent of total energy consumption in Sub-Saharan Africa (FAO 1987). Even though it was modest, the region experienced a rapid growth of its electric power sector until the economic crisis of the 1980s.

The downturn that occurred had a negative impact on the economy and the electric power sector. The electricity production of SubSaharan Africa is far below that of other major developing regions. Of the amount generated, mining and processing industries absorb up to 80 per cent, with a limited amount being consumed by households. As the consumption rate of electric power increases, the level should be maintained so that many more urban and suburban populations may be supplied with electricity. But the question is, how can this be achieved?

Economic and financial constraints on African countries have been major causes of the inadequate development and slackening growth of the power sector. Being the poorest of the developing countries, the deterioration of their terms of trade has affected their economic growth, which is further worsened by population explosion. The necessary investments for the energy sector are enormous. At the same time it appears that electrification in rural areas could help slow down rural-urban migration, which is on the increase, and pave the way for the conditions for sustained economic development. However, given that rural electrification programmes are capital intensive and usually unprofitable, the possibility of providing electric power to most of the rural population is a forlorn hope. For it is doubtful whether SubSaharan Africa has the potential to mobilize adequate resources to develop this sector.

None the less, technologies now exist for generating electricity based on renewable energy sources apart from hydropower generation. Solar photovoltaic systems, wind generators, and gasifiers are a few of the examples. In 1981, a national conference was organized on New and Renewable Sources of Energy (NARSE) by the United Nations in Rome. A lot of enthusiasm about these resources was generated but one has to be cautious about the technological developments suggested at such energy meetings. The conference painted a rosy and conflict-free picture of solar and wind energy projects. To this end, between 1981 and 1986 there was dissemination of solar and other renewable energy technologies. However, because oil was cheap at the time and the fuelwood crisis had not yet reared its ugly head, not much attention was devoted to research and development of these appropriate technologies.

With the oil crisis, industrial countries made efforts to expand their development endeavours in appropriate technology. In Africa, solar technology was seen as a potential alternative. It was even assumed that African countries could bypass an era of fossil fuel and switch straight to solar energy, which is abundant, ubiquitous, and free (Goodman 1985). But this was not to be realized on a large scale because economic constraints hindered the diffusion of the NARSE technologies. Those NARSE technologies, such as solar cookers, that were initially acceptable appear to have lost their original attraction. Other applications, including solar crop driers, solar water heaters for institutional applications, passive solar heating, wind pumps, and mini-hydro and big-energy in the form of biogas, have, however, achieved some measure of success.

Considering the existing status of NARSE, it seems the energy sector in SSA will continue to be largely based on wood fuels. But this does not mean that alternative sources must not be pursued. Wood energy must be seriously considered as an integral part of a global and multisectoral energy strategy.

In this connection, increasing numbers of action programme initiatives are being developed at both regional and national levels to harmonize and improve rational forest management and wood-fuel availability. Among the national programmes are the Desertification Control Programme, the Environmental Action Plan, and the Tropical Forest Action Plan, which have wood fuel as one of their priority areas. The regional programmes include the Inter-States Committee on Drought Control, the Intergovernmental Authority on Drought and Development, the Southern Africa Development Coordinating Conference, and the Agroforestry Network for Africa Programme.

Donor agencies have been particularly supportive in assisting developing countries to formulate and execute environmentally sound energy policies. One such example is the Energy Sector Management Assistance Programme funded by the United Nations Development Programme and the World Bank. This project, which operates in many African countries, has an elaborate research agenda that emphasizes the promotion of energy-efficient technologies and environmentally benign fuels.

Conclusion

By all indications the fuelwood paradox is a critical issue in the sustainable development of Sub-Saharan Africa. As the terms of trade of the countries of Africa deteriorate, it becomes even more difficult to allocate foreign exchange to petroleum imports and the development of new and renewable sources of energy, which are more efficient. As such, we could not agree better with Brooks that:

We cannot conceive of development without changes in the extent or nature of energy flows of Africa. And because energy is so fundamental, every one of those change flows has environmental implications. The implications of this are profound. It means that there is no such thing as a simple energy choice. They are all complex. And they will all involve trade-offs. However, some of the choices and some of the trade-offs appear to be unequivocally better than others, in the sense that they offer more development and less environmental damage. (Brooks 1986; cited in WCED 1987: 173)

Wood fuels offer least potential in economic and industrial development even though they are the predominant household fuel. In the short term, energy policies should include strategies for the production and supply of wood energy to ensure its consumption in a more sustainable manner.

To formulate an effective basis for doing this, due attention should be given to analysis of the special needs and priorities of rural populations with reference to women and community participation in identifying actions as well as decentralized energy planning. In the process of fuelwood supply, modified patterns should be determined through studies at the national level. Remunerative producer prices should also be established to satisfy urban fuelwood needs. Coupled with this, national and local programmes, including dissemination of cheap and efficient charcoal and wood-burning stoves, should be launched to reduce wood-fuel consumption.

The development of modern fuels such as coal, petroleum, and natural gas should be more fully explored and developed. National and international institutions should be encouraged to invest in the sector. Regional cooperation could also be explored as a useful instrument for furthering this goal and for enhancing energy development and independence in SSA. This cooperation has already been demonstrated with the formation of the African Petroleum Producers' Association (APPA) in 1987. Other regional groupings, as well as multilateral institutions, could help to accelerate sustainable energy development in the region.

References

Ardayfio, E. 1986. The Rural Energy Crisis in Ghana: Its Implications for Women's Work and Household Survival. Geneva: International Labour Organization.

Ardayfio-Schandorf, E. 1981. Rural Energy Production and Consumption in Southwestern Nigeria: The Role of Women. Obafemi Awolowo Univcrsity, Ile-lfe, Nigeria.

---- 1983. Rural energy consumption in south-western Nigeria. Bulletin of Ghana Geographical Association I (I).

---- 1993. Commercialization of fuelwood in Ghana. Paper presented at a Conference on Women and Forestry in Ghana, Accra.

Brooks, D. 1986. Friends of the Earth, cited in WCED, Our Common Furure. Oxford: Oxford University Press, 1987.

Cline-Cole, R. 1985. Energy, environment and man in tropical Africa: The case of the Freetown woodfuel market. Paper presented to the Bamako International Symposium on Urban-Rural Relationships, Bamako.

Eckholm, E. et al. 1984. Fuelwood: The Energy Crisis That Won't Go Away. London: Earthscan.

FAO (Food and Agriculture Organization of the United Nations). 1987. Ghana Forestry Project Preparation Report. Rome.

French D. 1978. Renewable Energy for Africa: Needs, Opportunities, Issues. Washington D.C.: United States Agency for International Development.

FRIDA (Fund for Research and Investment for the Development of Africa). 1980. Domestic Energy in Sub-Saharan Africa: The Impending Crisis. Its Measurement and Framework for Practical Solutions. London.

Gamser, M. S. 1980. The forest resource and rural energy development. World Development 8: 769-780.

Goodman, G. T. 1985. Energy and development. Where do we go? Ambio 14(4-5).

Leach, G. and R. Mearns. 1989. Beyond the Woodfuel Crisis: People, Trees and Land in Africa. London: Earthscan.

O'Keefe, M. 1990. A new energy agenda for Africa. Paper presented at the International Seminar on Energy in Africa, 27 30 November, Abidjan, Cote d'lvoire.

United Nations. 1990. United Nations Statistical Year Book.

WCED (World Commission on Environment and Development). 1987. Our Common Future. Oxford: Oxford University Press.

World Bank. 1992. World Development Report. Washington D.C.

(introduction...)

references

lloyd a. k. quashie

"sustainable development" implies that economic activity should be designed to create wealth for the use of present and future generations. if natural resources cannot be developed and exploited to create wealth for the nation, the result may be poverty and deprivation. crisis management soon takes over from sustainable economic development. so far, experience in sub-saharan africa for the past 20 years would indicate that almost all the countries in this region have suffered negative growth; that is, the economies of sub-saharan africa are in a state of decline and the development of the rich natural resources has come to a virtual standstill. the sub-saharan region has turned into a region of "beggar nations" in the midst of plentiful natural resources. in this regard, the least harnessed resources of this beautiful continent include minerals and energy.

the economic crisis has become endemic and is now becoming pandemic in the region. a solution to the problems must be found in order to reverse the condition of exponential decay and bring the countries back on the track of viable and sustainable economic growth.

the thesis of this paper is that the road to sustainable development and growth of the sub-saharan economies will be mainly via rational development and exploitation of the mineral and energy resources rather than by agricultural development. the track record of the subsaharan economies since independence, and certainly for the past 20 years, would support the argument that agriculture has so far failed as the engine for economic development in most countries of mainland sub-saharan africa. for example, countries such as cd'lvoire, senegal, and kenya have succeeded for only a limited period in using agriculture and agro-based industries as an "engine" for the sustainable growth of their economies.

on the other hand, countries such as botswana, zimbabwe, and, more recently, ghana have proved that a country with a strong minerals industry and a cheap energy resource can aspire to positive economic growth that can be sustained, depending on the life of the resource and changes in demand, and can also provide the necessary catalyst for the development of other sectors of the economy. this growth pattern has also been the backbone of the sustainable development of certain industrialized countries such as the united states, canada, some west european countries, and australia. other highly developed countries lacking or with only limited mineral and energy resources, such as germany (i.e. former west germany) and japan, have had to import the necessary mineral raw materials and fuel energy to feed and sustain their huge industrial base for economic growth.

the industrialized countries would rather hoard or subsidize agricultural production, much to the detriment or the disadvantage of the developing countries, in particular sub-saharan africa, which provide most of the mineral raw materials and part of the fuel energy for the industrialized countries. production of selected minerals by the leading producing countries in sub-saharan africa in 1989 is shown in table 14.1 and the value of minerals exported in 1989 in table 14.2.

in order for sub-saharan africa to recover from its development stagnation, it is imperative that a new development agenda be forged, with more emphasis on the exploration, development, exploitation, and rational management of its mineral and energy resources for sustainable economic growth. curbing population growth or demobilizing the public sector of the economy cannot open the gates to sustainable development in the medium to long term. preserving the pristine countryside in the interests of good environmental practice and health would also cause the otherwise necessary industrial development of the subregion to stagnate. a happy medium has to be found between unguarded development and sustainable development that takes into account the health of the population and the preservation of a sound environment for future generations.

table 14.1 sub-saharan africa: major mineral producers and share of world mine supply, 1989 (volume of selected minerals)

country	mineral
	copper '000 m.t.	bauxite '000 m.t.	rutile m.t.	diamonds '000 carats	manganese ore '000 m.t.	cobalt m.t.	uranium '000 m.t.
angola	-	-	-	1,272	-	-	-
botswana	22	-	-	15,251	-	-	-
car	-	-	-	447	-	-	-
gabon	-	-	-	-	2,600	-	900
ghana	-	382	-	290	280	-	-
guinea	-	17,547	-	230	-	-	-
namibia	38		-	932	-	-	3,629
niger	-	-	-	-	-	-	2,962
sierra leone	-	1,562	128	600	-	-	-
swaziland	-	-	-	55	-	-	-
zaire	430	-	-	17,652	-	8,314	-
zambia	445	-	-	-	-	4,490	-
zimbabwe	16	-	-	-	-	-	-
total ssa	951	19,491	128	36,729	2,880	12,804	7,491
world supply	9,082	107,963	450	98,500	22,100	19,867	35,586
ssa share	11%	18%	28%	37%	13%	64%	21%

source: world bank (1992: 1).

table 14.2 sub-saharan africa: value of mineral exports, 1989 (us$ m.)

country	minerala
	copper	bauxite	ore	gold	diamonds and gems	lead/ zinc	manganese ore	nickel	tin	cobalt	uranium	phosphate rock		misc. total
angola	-	-	-	-	230	-	-	-	-	-	-	-	-	230
botswana	60	-	-	-	1,300	-	-	140	-	-	-	-	-	1,500
burkina faso	-			30	-	-	-			-	-	-	-	30
car	-	-	-	-	40	-	-	-	-	-	-	-	-	40
gabon	-	-	-	-	-	-	175	-	-	50	-	-	-	225
ghana	-	5	-	150	15	-	15	-	-	-	-	-	-	185
guinea	-	400		45	55	-	-	-	-	-	-	-	130	630
liberia	-	-	200	-	-	-	-	-	-	-	-	-	-	200
mali	-	-	-	25	-	-	-	-	-	-	-	-	-	25
mauritania	-		180	-	-	-		-	-	-	-	-	-	180
namibia	125	-	-	10	320	60	-	-	10	250	-	-	25	800
senegal	-	-	-	-	-	-	-	-		-	-	80	-	80
sierra leone	-	25	-	-	10	-	-	-	-	-	-	-	55	90
swaziland	-	-	-	-	20	-	-	-	-	-	-	-	10	30
togo	-	-	-	-	-	-	-	-	-	-	-	115	-	115
zaire	1,245	-	-	30	250	90	-	-	15	170	-	-	-	1,800
zambia	1,230	-	-	-	-	40	-	-	-	70	-	-	-	1,340
zimbabwe	30	-	10	175	-	-	-	110	-	-	-	-	85	410
others	-	-	-	15	10	-	-	-	15	-	-	-	20	60
total formal	2,690	430	390	480	2,250	190	190	250	40	240	530	195	325	8,200
artisanal/informal	-	-	-	300	500	-	-	-	-	-	-	-	-	800
total ssab	2,690	430	390	780	2,750	190	190	250	40	240	530	195	325	9,000

source: world bank (1992: 2).

a. excludes aluminium exports of about us$300 million from ghana and cameroon.
b. over 95 per cent of ssa's mineral production is estimated to be exported and available statistics do not readily permit a separation of the value of production and the value of exports.

africa is almost certainly endowed with enormous mineral resources yet to be discovered. exploration for these mineral resources has not been conducted in a systematic manner since independence in the sub-saharan countries. as such, the full impact of the minerals industry sector on the economies of these countries has been minimal or non-existent. the countries that could boast of a significant minerals industry sector are: botswana, ghana, guinea, zaire, zambia, zimbabwe, and the republic of south africa; including oil, one would add nigeria, gabon, and angola (see table 14.3). these countries, however, had a mining tradition during colonial times and in several cases even before. some governments built strong geological surveys, mining, and metallurgical departments, which conducted geological mapping and exploration of known mineral deposits (usually ancient artisanal mining sites) for allocation to mining companies for development and exploitation. the mining leases granted by the colonial governments virtually gave the companies perpetual mineral rights and tenure on very disadvantageous terms to the colonies.

upon the attainment of independence, these countries enacted new mining laws, which vested the minerals resources in the state. the countries therefore achieved sovereign rights over the mineral deposits (including petroleum and natural gas) with a view to exploiting these resources, this time more to the benefit of these sovereign nations. however, with the exception of the republic of south africa, and recently botswana, none of the sub-saharan countries can boast of a strong and viable minerals industry sector in their economies that could contribute to sustainable development in the coming decades. so far, attempts to develop the mineral resources of these countries have been limited to half-hearted policy reforms and the enactment of mining legislation and investment codes, which have failed to attract the necessary investment in the minerals industry sector. many factors have contributed to the poor performance of the minerals industry sector of the sub-saharan countries. however, before proceeding to discuss these factors, i should like to examine the new slogan "sustainable development" as it may be applied to mineral management and development in the africa region.

table 14.3 sub-saharan africa: the economic contribution of mining, selected countries, 1989

country	formal mining exports(us$ m.)	mining exports as % of total exports	mining value- added as % of gdp	mineral taxes as % of total taxes
zaire	1,798	83	16	35
botswana	1,506	83	51	58
zambia	1,337	95	13	16
namibia	799	76	29	36
guinea	627	82	25	72
zimbabwe	411	26	6	n.a.
niger	232	75	6	16
angola	230	8	2	n.a.
gabon	225	16	5	n.a.
liberia	200	58	n.a.	n.a.
ghana	186	23	2	n.a.
mauritania	181	41	10	n.a.
togo	115	22	8	n.a.
sierra leone	89	80	6	5
senegal	76	10	i	n.a.
car	40	25	3	n.a.
burkina faso	33	15	1	n.a.
swaziland	30	10	1	n.a.
mali	25	9	1	1
total	8,140	47	10	30a

source: world bank (1992: 3). a. estimate.

minerals occur naturally in the subsoil and they have to be discovered by systematic exploration. their distribution in the subsoil is governed by certain physical and chemical principles, host-rock characteristics, and the structural history of the mineral location. unlike crops, minerals cannot be planted, watered, fertilized, or made to grow to produce "food" to feed the nation. the mineral endowment of a country can be made available for utilization only through sustained investment in systematic exploration, development, mining, and processing. the minerals that can be developed, mined, and processed economically should occur in such proven quantities and grades that they may contribute to the wealth and growth of the economy when exploited. a viable mineral enterprise should also be able to generate sufficient funds from operations to finance further exploration and development of the mineral resource base for future exploitation, otherwise the enterprise will perish. without exploration for ore reserves there can be no sustainable development of a mining enterprise and the sector cannot contribute to economic growth for the future wealth of the nation.

in the minerals industry, "sustainable development" would therefore imply sustained investment in exploration and development to access economic ore deposits for extraction and for use at a profit. there are, however, certain imperatives for the development of a strong and viable minerals industry sector. it needs a realistic management and administrative policy that takes account of the needs of society and, at the same time, guarantees equitable distribution of the wealth generated by the mineral asset to the investor and the host country. this mineral development policy should be stable in the long term in order to attract the much-needed investment in the sector, which, by its very nature, is "high risk" and requires long lead-times for development, start-up, and operations. above all, society is now demanding that mining operations should, in addition to contributing to wealth, be environmentally friendly and sustainable for the use of future generations. this is what a rational and realistic mineral development policy has always been about. this policy has been described as a "mineral conservation policy" by economic geologists, and progressive mining laws and regulations include provision for such a policy. sustainable environmental practice should be compatible with good mining industrial practice. good mining practice should also take into account the health and safety of the workers and the people living near the mining operations.

furthermore, mineral conservation requires that the depletion rate of the mineral deposit should be in balance with the rate of discovery of mineable reserves and in accordance again with good environmental practice. environmentalists have tended to confuse conservation of the natural resource and environment with preservation, an attitude that may preclude the utilization and development of natural resources.

if all these factors and policy issues are brought into harmony under mineral development legislation and fiscal regimes that are realistic and dynamic, sustainable development of the minerals industry could be carried out for economic growth to meet the basic needs of the population, while conserving the natural resource base for the socio-economic needs of future generations in a sound environment. however, botswana should be singled out for special mention as the only country that has been able to develop its mineral sector as an "engine" for economic growth during the past 10 years.

the country is blessed with minerals of very high intrinsic value, a realistic mineral legislation policy, and a relatively stable investment climate. after many decades of massive investment in agriculture and agro-based industries, botswana has shown that agriculture alone cannot suffice to sustain economic development. many constraining factors have contributed to the near-stagnation of the development of the minerals industry in the sub-saharan economies. these factors occur in varying degrees from country to country, but those that are fundamental and common to all the countries are identified briefly below:

a lack of investment in systematic geological mapping and exploration, and inadequate technical data on the mineral endowment;

a weak institutional and policy framework for mineral development and exploitation;

inadequate fiscal and financial regimes for mining development;

poorly developed infrastructural bases, including transportation, communications, and engineering services;

a lack of cheap, reliable energy resources for industrial projects;

the deterioration of the economic performance of the sub-saharan countries, exacerbated by deteriorating terms of trade and inadequate pricing of primary mineral commodities produced by these countries;

the unusually high cost of capital for mining projects in the region compared with the capital cost of similar mining projects in southeast asia, australia, and south america;

the perception by the international mining community of an unstable "investment climate," political instability, and corruption in sub-saharan africa;

the scarcity of indigenous professional and technical manpower capable of formulating viable policy reforms, estimating the feasibility of mineral development projects, or negotiating equitable joint-venture mining agreements with transnational corporations.

despite these difficulties, the sub-saharan countries should be able to develop their mineral resources as an "engine" for sustainable growth and in an environmentally friendly manner. the continent is endowed with enormous mineral potential, including: diamonds, gold, silver, the platinum group metals, emeralds, rubies, and other semi-precious minerals, bauxite, manganese, nickel, cobalt, copper, cadmium, chrome, lead, zinc, and other non-ferrous metals, iron ores (hematite and magnetite), cassiterite, rutile, ilmenite, zirchon, monazite, mica, vermiculite, limestone, gypsum, barytes, potash, phosphase, kaolin, "granites" for dimensional stones, and other industrial minerals. africa is also known for proven reserves of high-quality petroleum, natural gas, peat, lignite, and coal with low sulphur content (i.e. gondwana coal). african countries are yet to develop these rich mineral resources and exploit them for industrialization and sustained growth. the world bank (1989: 122) describes the "relative mineral abundance" as a "mixed blessing" to many african countries. it could also be described as a situation of poverty in the midst of plenty!

however, the failure to develop the full potential of the minerals industry in the sub-saharan economies is not entirely the fault of the governments concerned. certain important exogenous factors have also contributed to the near-stagnation of the development agenda of the african countries. for the past 20 years, africa has missed the investment boom of international finance in mineral exploration and development. most of the mining investments have been directed away from africa to south america, canada, australia, papua new guinea, and the fast-growing countries of south-east asia (see fig. 14.1). some of these apparently more attractive countries have little comparative advantage in terms of political stability. in fact, there is evidence that many of the transnational corporations that were operating profitably in africa during colonial times pulled out of africa just before or immediately after independence to invest in mining ventures elsewhere. fortunately for sub-saharan africa, many of the ventures have failed in those countries and the africa region has another opportunity to attract the transnational corporations back to the very high-grade near-surface ore deposits of the continent that they virtually abandoned more than 20 years ago. the country most likely to offer stiff competition for scarce mining venture capital over the next few years is australia. however, the mining companies of australia have already committed most of their sales contracts for the supply of mineral products to japan and the asean countries, which until recently have been experiencing an economic boom.

in today's sub-saharan africa investors will find the host countries more realistic in asserting their sovereign rights over natural resources. the private sector will be encouraged to participate in the development of mineral resources without undue intervention from the state. governments are more prepared to confine themselves to the roles of good landlord and regulator of the industry. investment codes have been enacted that have entrenched in them special bene fits and incentives for investing in the mining sector.

more competitive and stable fiscal and financial regimes have been passed into law with guarantees for the repatriation of capital and profits. however, the host countries also expect a fair and equitable share of the revenues generated from the mining operations for financing sustainable development and the growth of their economies. having undertaken painful macroeconomic reforms in order to attract foreign investment, these countries will expect that joint-venture mining projects would not be operated as offshore or enclave enterprises and that they would be more integrated into the domestic economies and become net foreign exchange earners. import substitution projects would be encouraged only if it could be demonstrated that they would conserve foreign exchange, that the products would be of high quality, and that they would be sold at competitive prices. host countries would also expect that the plant employed for added-value processing of minerals and mineral products would utilize proven technology that reduces unit costs and does little or no damage to the environment.

Fig. 14.1 Comparison of minerul production in Africa, Asia, and Latin AmericaCaribbean for eight selected minerals and metals, 1960-2000 (1985 [IS$ billion) (Note: actual and projected gross value of production of aluminium, copper, iron ore, zinc, nickel, lead, tin, and gold. Source: World Bank 1992: 5)

As discussed above, in my view agriculture has failed to provide a satisfactory engine for growth in the past two decades in several SubSaharan countries. The monocultural export economies of developing countries, and of Africa in particular, have suffered heavily from worsening terms of trade. Apart from poor agricultural commodity prices, war and drought have exacerbated the situation in the region. The devastation of the human ecology and the environment by war and plunder is often overlooked or taken for granted by the so-called animal lovers and Greenpeace activists. There is also evidence that large-scale farm mechanization and the application of chemical fertilizers have damaged the soils in some areas of intensive agricultural development, although Sub-Saharan Africa uses less chemical fertilizer than any other major global region. However, it must be recognized that countries whose economies are "mono-mineralic" are also vulnerable to the vagaries of the international mineral market, with the exception to some extent of the countries that produce precious minerals such as gold and gemstones.

Countries that are endowed with both large areas of fertile/arable land and mineral resources stand the best chance of stable economic development. The majority of African countries fall into this category. The Republic of South Africa (RSA) is the only country with a strong and long-lasting mining tradition in the Sub-Sahara that has successfully developed its minerals industry as the backbone of its economy, including the agricultural sector. It should also be noted that the mining industry of the RSA is fully integrated into the domestic economy with minimal foreign exchange content in the cost of operations. The country possesses efficient and competitive import-substitution industries, and the minerals and metals exporting companies are net foreign exchange earners. There are no "enclave" or "offshore" transnational enterprises in the RSA. The government regulates and intervenes to rescue the industry during bad times and participates in the revenue via royalties, not by equity holdings. The fundamental difference here is that the currency of the RSA is freely convertible into prime currencies and has purchasing power. This makes the investment climate very attractive, in spite of political instability.

The objectives set more than 30 years ago by many Sub-Saharan countries to exploit their mineral and energy resources for import substitution and value-added production of manufactures have not been achieved. Although there are indications of mineral deposits of economic value, the exploration effort in many countries has been inadequate or non-existent. Informal artisanal mining, particularly for gold, diamonds, emeralds, rubies, and amethyst, and small-scale quarrying for industrial minerals and aggregate are the main activities in the mining sector.

Large-scale mining of iron ore, non-ferrous metals (e.g. copper, bauxite, manganese, nickel), petroleum products, and coal is undertaken by transnational corporations in economic enclaves, and the products are exported as concentrates with very little or no added value. For the foreseeable future, many of the SubSaharan countries will be unable to establish downstream processing/ extraction plants to refine and produce finished products of metals and mineral substances. The continent will for a long period remain a primary producer of metal and mineral raw materials for the industrialized countries of the North. As such, environmental degradation and pollution are more likely to occur at the mining and ore-dressing stage. Those countries that would like to establish downstream plant for the production of finished products should beware of the dumping of obsolete technology by companies that may be forced to sell old plant owing to the environmental regulations of their home countries. For the present and immediate future the areas of environmental concern include the following mining-related activities:

large-scale open-pit operations (e.g. porphyry copper deposits, bauxite, lateritic nickel, manganese, phosphate rock, oxidized gold ores, and placer deposits);

large-scale dredging operations in rivers with extensive drainage systems and in beach sands;

roasting of refractory ores containing arsenic, sulphides, and radioactive substances;

open-pit coal mining and processing of coal and briquetting;

small-scale mining, especially alluvial mining of gold and diamonds, and the use of toxic chemicals and unsafe mining methods by artisanal operators;

metallurgical processing, extraction, refining, and manufacture of metals and chemicals for local use and for export to earn foreign exchange.

Environmental impact assessment of the above mining activities and control measures should be instituted with the objective of conserving the environment for the well-being of the present generation and for future use. There is an urgent need to develop an implementable environmental policy that will promote the efficient extraction and utilization of the mineral and energy resources of Africa in order to achieve sustainable growth. Failure to explore, access, and develop the natural resources for fear of damaging the countryside will bring only economic stagnation, poverty, disease, and degradation of life in the Sub-Saharan countries. Environmental preservation is not the same as environmental conservation. Furthermore, preservation of the natural resources should not be confused with conservation of the ecological equilibrium of an area. The former attitude is fraught with hypocrisy and the latter takes account of the realities and imperatives of sustainable development and sustainable economic growth. It is the great industrial countries that are the greatest polluters of the earth's environment. The African countries should learn some useful lessons from the industrialized countries if they are ever going to break the spiral of decay and poverty in the midst of plenty. The natural resources must be harnessed for economic development and growth. There is no other alternative for Africa's survival and sustainability in the global environment.

Minerals have to be mined where they are found. Fortunately, they are usually found in remote locations where industrial activity is nonexistent, and the environment itself is sensitive to sudden change. As such, an environmental impact assessment must be carried out by the investing company in cooperation with decision makers of the government. Both sides must be environmentally aware so that environmental protection needs may be determined realistically before the implementation of the mining project. Preliminary information gathered in a "green-field" area should provide the baseline or reference point for future assessment and monitoring of the impacts of the mining operations on the environment. Many industrialized countries of the North, particularly in Eastern Europe, with long histories of mining minerals, processing, and the use of low-grade fuels, are now paying the price for not tackling the problems of damage to the health of the population and complete destruction of the environment.

However, legislation that sets standards for environmental protection should not be onerous or non-implementable. It should be dynamic and, as much as possible, should be project specific because every mining project is different and specific to a particular area.

Finally, it is very important that management and the entire workforce on a mining project are made aware of their responsibilities to the environment in which they are working and making a living. Many of the workers may not originate from the area and management must endeavour to maintain this awareness from top to bottom throughout the life of the project cycle. Environmental impact studies and assessment methods are relatively new in the curriculum of minerals industry schools. The Sub-Saharan countries should strengthen their institutional capacity to monitor environmental impacts through sustained training. Training of indigenous personnel in environmental work should be provided for in all agreements with developers. Training in environmental assessment methods is an area where the bilateral and multilateral organizations could make a valuable contribution to human resource development for capacity-building in Africa.

I hope that I have been able to put the case for the need to institute a rational, pragmatic, and, above all, realistic policy reform in SubSaharan Africa for the sustained exploration and development of its minerals and energy resources for the creation of wealth on an exponential basis to sustain the improved well-being of its longsuffering population and for the survival of future generations. What Sub-Saharan Africa has experienced so far is the decay of economies supervised by incompetent governments, the majority of which have no democratic mandate to rule their people. I refuse to believe that Africa cannot succeed. Given the right political atmosphere, free from utopian and unworkable foreign ideologies, the intelligent and enterprising people of Africa, at all levels of society, can and should be allowed to develop the economy for sustainable growth. Africa is not short of intelligent, capable, and experienced people. They have been prevented from participating in the development process for the past 30 odd years, during which private initiative, entrepreneurship, and the private sector of the economies were destroyed. I pray that it will not take that long to rebuild the mining sector and bring African countries back to the path of sustainable development and social equity.

References

World Bank. 1989. Sub-Saharan Africa: From Crisis to Sustainable Growth. Washington D.C.: World Bank.

---- 1992. Strategy for African Mining. Technical Paper no. 181. Washington D.C. World Bank.